JO iPath Series B Bloomberg Coffee Subindex TR ETN

Subject to Completion

Terms used in this preliminary pricing supplement, but not defined herein, shall have the meanings ascribed to them in the prospectus supplement.

Investing in the Notes involves a number of risks. See “Risk Factors” beginning on page S-6 of the prospectus supplement and “ Selected Risk Considerations ” beginning on page PPS-5 of this preliminary pricing supplement.

The Notes will not be listed on any U.S. securities exchange or quotation system. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined that this preliminary pricing supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The Notes constitute our direct, unconditional, unsecured and unsubordinated obligations and are not deposit liabilities of Barclays Bank PLC and are not insured by the U.S. Federal Deposit Insurance Corporation or any other governmental agency of the United States, the United Kingdom or any other jurisdiction.

You may revoke your offer to purchase the Notes at any time prior to the pricing as described on the cover of this preliminary pricing supplement. We reserve the right to change the terms of, or reject any offer to purchase the Notes prior to their issuance. In the event of any changes to the terms of the Notes, we will notify you and you will be asked to accept such changes in connection with your purchase. You may also choose to reject such changes in which case we may reject your offer to purchase.

ADDITIONAL TERMS SPECIFIC TO THE NOTES

You should read this preliminary pricing supplement together with the prospectus dated August 31, 2010, as supplemented by the prospectus supplement dated May 27, 2011 relating to our Global Medium-Term Notes, Series A, of which these Notes are a part. This preliminary pricing supplement, together with the documents listed below, contains the terms of the Notes and supersedes all prior or contemporaneous oral statements as well as any other written materials including preliminary or indicative pricing terms, correspondence, trade ideas, structures for implementation, sample structures, brochures or other educational materials of ours. You should carefully consider, among other things, the matters set forth under “Risk Factors” in the prospectus supplement, as the Notes involve risks not associated with conventional debt securities. We urge you to consult your investment, legal, tax, accounting and other advisors before you invest in the Notes.

You may access these documents on the SEC website at www.sec.gov as follows (or if such address has changed, by reviewing our filings for the relevant date on the SEC website):

http://www.sec.gov/Archives/edgar/data/312070/000119312510201448/df3asr.htm

http://www.sec.gov/Archives/edgar/data/312070/000119312511152766/d424b3.htm

http://www.sec.gov/Archives/edgar/data/312070/000119312511154632/d424b3.htm

Our SEC file number is 1-10257. As used in this preliminary pricing supplement, the “Company,” “we,” “us,” or “our” refers to Barclays Bank PLC.

What is the Total Return on the Notes at Maturity Assuming a Range of Performance for the ETF?

The following table illustrates the hypothetical total return at maturity on the Notes. The “total return” as used in this preliminary pricing supplement is the number, expressed as a percentage, that results from comparing the payment at maturity per $1,000 principal amount Note to $1,000. The hypothetical total returns set forth below are for illustrative purposes only and may not be the actual total returns applicable to a purchaser of the Notes. The numbers appearing in the following table and examples have been rounded for ease of analysis. Note that, for purposes of the hypothetical total returns set forth below, we are assuming a hypothetical Initial Price of $87.34, a Maximum Return of 17.70% and the Buffer Percentage of 20.00%. The examples below do not take into account any tax consequences from investing in the Notes.

Hypothetical Examples of Amounts Payable at Maturity

The following examples illustrate how certain total returns set forth in the table above are calculated.

Example 1: The price of the ETF increases from an Initial Price of $87.34 to a Final Price of $91.71.

Because the Reference Asset Return of 5.00% does not exceed the Maximum Return of 17.70%, the investor will receive (subject to our credit risk) a payment at maturity of $1,050.00 per $1,000.00 principal amount Note calculated as follows:

$1,000 + [$1,000 × Reference Asset Return]

$1,000 + [$1,000 × 5.00%] = $1,050.00

The total return on the investment of the Notes is 5.00%.

Example 2: The price of the ETF decreases from an Initial Price of $87.34 to a Final Price of $74.24.

Because the Final Price of $74.24 is less than the Initial Price of $87.34 by a percentage equal to or less than the Buffer Percentage of 20.00%, the investor will receive (subject to our credit risk) a payment at maturity of $1,000 per $1,000 principal amount Note.

The total return on the investment of the Notes is 0.00%.

Example 3: The price of the ETF increases from an Initial Price of $87.34 to a Final Price of $104.81.

Because the Reference Asset Return of 20.00% exceeds the Maximum Return of 17.70%, the investor will receive (subject to our credit risk) a payment at maturity of $1,177.00 per $1,000.00 principal amount Note, the maximum total payment on the Notes.

The total return on the investment of the Notes is 17.70%.

Example 4: The price of the ETF decreases from an Initial Price of $87.34 to a Final Price of $61.14.

Because the Final Price of $61.14 is less than the Initial Price of $87.34 by more than the Buffer Percentage of 20.00%, the investor will receive (subject to our credit risk) a payment at maturity of $900.00 per $1,000.00 principal amount Note calculated as follows:

$1,000 + [$1,000 × (Reference Asset Return + Buffer Percentage)]

$1,000 + [$1,000 × (-30.00% + 20.00%)] = $900.00

The total return on the investment of the Notes is -10.00%.

PPS-3

Selected Purchase Considerations

In the opinion of our special tax counsel, Sullivan & Cromwell LLP, it would be reasonable to treat your Notes in the manner described below. This opinion assumes that the description of the terms of the Notes in this preliminary pricing supplement is materially correct.

The United States federal income tax consequences of your investment in the Notes are uncertain and the Internal Revenue Service could assert that the Notes should be taxed in a manner that is different than described below. Pursuant to the terms of the Notes, Barclays Bank PLC and you agree, in the absence of a change in law or an administrative or judicial ruling to the contrary, to characterize your Notes as a pre-paid cash-settled executory contract with respect to the ETF. Subject to the discussion of Section 1260 below, if your Notes are so treated, you should generally recognize capital gain or loss upon the sale or maturity of your Notes in an amount equal to the difference between the amount you receive at such time and the amount you paid for your Notes. Such gain or loss should generally be long-term capital gain or loss if you have held your Notes for more than one year.

Although not entirely clear, it is possible that the purchase and ownership of the Notes could be treated as a “constructive ownership transaction” with respect to the ETF that is subject to the constructive ownership rules of Section 1260 of the Internal Revenue Code. If your Notes were subject to the constructive ownership rules, then any long-term capital gain that you realize upon the sale or maturity of your Notes that is attributable to the appreciation of the ETF over the term of your Notes would be recharacterized as ordinary income to the extent that such long-term capital gain exceeds the amount of long-term capital gain that you would have realized had you purchased the actual number of shares of the ETF referenced by your Notes on the date that you purchased your Notes and sold those shares on the date of the sale or maturity of the Notes (the “Excess Gain Amount”), and you would be subject to an interest charge on the deferred tax liability with respect to such Excess Gain Amount. Because, in general, the maturity payment of the Notes will only reflect the appreciation or depreciation in the value of the shares of the ETF and will not be determined by reference to any short-term capital gains or ordinary income, if any, that is recognized by holders of shares of the ETF, and because there is no upside leverage on the Notes, we believe that (subject to the discussion below) the Excess Gain Amount should be equal to zero, and that the application of the constructive ownership rules should accordingly not have any adverse effects to you. However, if you purchase your Notes at a discount, it is possible that the Excess Gain Amount could be greater than zero if the Internal Revenue Service successfully asserts that the discount at which you purchase your Notes should be taken into account in determining the Excess Gain Amount Furthermore, if another exchange traded fund is substituted for the ETF, the Excess Gain Amount could be greater than zero if you would have recognized short-term capital gain if you had directly owned the ETF and sold the ETF to purchase its substitute. You should be aware that, if the Notes are subject to the constructive ownership rules, the Excess Gain Amount will be presumed to be equal to all of the gain that you recognize in respect of the Notes (in which case all of such gain would be recharacterized as ordinary income that is subject to an interest charge) unless you provide clear and convincing evidence to the contrary. Because the application of the constructive ownership rules to the Notes is unclear, you are strongly urged to consult your tax advisor with respect to the possible application of the constructive ownership rules to your investment in the Notes.

As discussed further in the accompanying prospectus supplement, the Treasury Department and the Internal Revenue Service are actively considering various alternative treatments that may apply to instruments such as the Notes, possibly with retroactive effect.

PPS-4

For a further discussion of the tax treatment of your Notes as well as possible alternative characterizations, please see the discussion under the heading “Certain U.S. Federal Income Tax Considerations—Certain Notes Treated as Forward Contracts or Executory Contracts” in the accompanying prospectus supplement. You should consult your tax advisor as to the possible alternative treatments in respect of the Notes. For additional, important considerations related to tax risks associated with investing in the Notes, you should also examine the discussion in “Selected Risk Considerations—Taxes”, in this preliminary pricing supplement.

“Specified Foreign Financial Asset” Reporting. Under legislation enacted in 2010, owners of “specified foreign financial assets” with an aggregate value in excess of $50,000 (and in some circumstances, a higher threshold) may be required to file an information report with respect to such assets with their tax returns. “Specified foreign financial assets” generally include any financial accounts maintained by foreign financial institutions, as well as any of the following (which may include your Notes), but only if they are not held in accounts maintained by financial institutions: (i) stocks and securities issued by non-U.S. persons, (ii) financial instruments and contracts held for investment that have non-U.S. issuers or counterparties and (iii) interests in foreign entities. Holders are urged to consult their tax advisors regarding the application of this legislation to their ownership of the Notes.

Non-U.S. Holders . The Treasury Department has issued proposed regulations under Section 871(m) of the Internal Revenue Code which could ultimately require us to treat all or a portion of any payment in respect of your Notes as a “dividend equivalent” payment that is subject to withholding tax at a rate of 30% (or a lower rate under an applicable treaty). You could also be required to make certain certifications in order to avoid or minimize such withholding obligations, and you could be subject to withholding (subject to your potential right to claim a refund from the Internal Revenue Service) if such certifications were not received or were not satisfactory. You should consult your tax advisor concerning the potential application of these regulations to payments you receive with respect to the Notes when these regulations are finalized.

Selected Risk Considerations

An investment in the Notes involves significant risks. Investing in the Notes is not equivalent to investing directly in the ETF. These risks are explained in more detail in the “Risk Factors” section of the prospectus supplement, including the risk factors discussed under the following headings:

In addition to the risks described above, you should consider the following:

Any payment on the Notes, including any principal protection feature, is subject to the creditworthiness of the Issuer and is not guaranteed by any third party. For a description of risks with respect to the ability of Barclays Bank PLC to satisfy its obligations as they come due, see “Credit of Issuer” in this preliminary pricing supplement.

PPS-5

PPS-6

PPS-7

DESCRIPTION OF THE ETF

We urge you to read the following section in the accompanying prospectus supplement: “Reference Assets—Exchange-Traded Funds—Reference Asset Investment Company and Reference Asset Information”. Companies with securities registered under the Securities Exchange Act of 1934, as amended, which is commonly referred to as the “Exchange Act”, and the Investment Company Act of 1940, as amended, which is commonly referred to as the “’40 Act”, are required to periodically file certain financial and other information specified by the SEC. Information provided to or filed with the SEC electronically can be accessed through a website maintained by the SEC. The address of the SEC’s website is http://www.sec.gov. Information provided to or filed with the SEC pursuant to the ’40 Act by the company issuing the ETF (“ETF Issuer”) can be located by reference to the SEC file number specified below.

We have derived all information contained in this preliminary pricing supplement regarding the ETF, including, without limitation, its make-up, method of calculation and changes in its components, from the Prospectus (the “Prospectus”) for the ETF dated August 1, 2012 issued by iShares Trust (the “Trust”). Such information reflects the policies of, and is subject to change by, the Trust and Blackrock Fund Advisors, which serves as an investment adviser to iShares ^® ETFs. You are urged to refer to the SEC filings made by the ETF Issuer and to other publicly available information (such as the ETF Issuer’s annual report) to obtain an understanding of the ETF Issuer’s business and financial prospects. The summary information contained below is not designed to be, and should not be interpreted as, an effort to present information regarding the financial prospects of any issuer or any trends, events or other factors that may have a positive or negative influence on those prospects or as an endorsement of any particular issuer or exchange-traded fund.

The ETF seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Underlying Index. Shares of the ETF are listed and traded on the NYSE Arca Stock Exchange under the ticker symbol “IWM”. The ETF generally invests at least 90% of assets in the securities of the Underlying Index and in depositary receipts representing securities in the Underlying Index. The Underlying Index measures the performance of the small-capitalization sector of the U.S. equity market. The Underlying Index is a subset of the Russell 3000 ^® Index. For additional information about the Underlying Index, see the information set forth below under “Russell 2000 ^® Index” in this preliminary pricing supplement.

Information provided to or filed with the SEC by the ETF pursuant to the Exchange Act and the ’40 Act can be located by reference to SEC file number 0333-92935 and 811-09729, respectively. Additional information regarding the ETF is available at the iShares ^® website at http://www.ishares.com. Information from outside sources is not incorporated by reference in, and should not be considered part of, this preliminary pricing supplement or any accompanying prospectus or prospectus supplement. We have not undertaken any independent review or due diligence of the ETF’s SEC filings or of any other publicly available information regarding the ETF.

Dislcaimer

iShares ^® is a registered mark of BlackRock Institutional Trust Company, N.A. (“BITCNA”). BITCNA has licensed certain trademarks and trade names of BITCNA to Barclays Bank PLC. The Notes are not sponsored, endorsed, sold or promoted by BITCNA. BITCNA makes no representations or warranties to the owners of the Notes or any member of the public regarding the advisability of investing in the Notes. BITCNA has no obligation or liability in connection with the operation, marking, trading or sale of the Notes.

RUSSELL 2000 ^® INDEX

All information regarding the Russell 2000 ^® Index or the Underlying Index set forth in this preliminary pricing supplement reflects the policies of, and is subject to change by, Russell Investments (“Russell”), the index sponsor. The Russell 2000 ^® Index was developed by Russell and is calculated, maintained and published by Russell. The Russell 2000 ^® Index is reported by Bloomberg under the ticker symbol “RTY <Index>”.

The Russell 2000 ^® Index is designed to track the performance of the small capitalization segment of the U.S. equity market. As a subset of the Russell 3000 ^® Index (the “Russell 3000”), it consists of approximately 2,000 of the smallest companies (based on a combination of their market capitalization and the current index membership) included in the Russell 3000 and represented, as of December 31, 2012, approximately 10% of the total market capitalization of the Russell 3000. The Russell 3000, in turn, comprises the 3,000 largest U.S. companies as measured by total market capitalization, which together represented, as of December 31, 2012, approximately 98% of the investable U.S. equity market.

PPS-8

Selection of Stocks Underlying the Russell 2000 ^® Index

Security Inclusion Criteria

All Russell indices, including the Russell 2000 ^® Index, are reconstituted annually to reflect changes in the marketplace. The companies that meet the eligibility criteria are ranked on the last trading day of May of every year based on market capitalization using data available at that time, with the reconstitution taking effect as of the first trading day following the last Friday of June of that year. If the last Friday in June is the 28th, 29th or 30th day of June, reconstitution will occur the Friday prior.