BHP Billiton announces that BHP Billiton Limited and BHP Billiton Plc have entered into an irrevocable arrangement with an independent third party which makes its trading decisions in relation to the securities of BHP Billiton Limited and BHP Billiton Plc independently of, and uninfluenced by, BHP Billiton Limited or BHP Billiton Plc, to purchase on BHP Billiton Limited's behalf and within certain pre-set parameters, ordinary shares in BHP Billiton Plc during the period commencing on 1 January 2007 and ending upon the announcement of BHP Billiton's interim results for the half year ended 31 December 2006. These share purchases will be made on BHP Billiton Limited's behalf and in accordance with the irrevocable arrangement during a so-called "Close Period", a period in which BHP Billiton and its directors, officers and employees would normally otherwise refrain from transacting in BHP Billiton shares.

Any share purchases effected pursuant to the irrevocable arrangement will be subject to the terms of the mandate and in any case will be effected in a manner consistent with both the general authority vested in BHP Billiton to repurchase shares and Chapter 12 of the Listing Rules, which require that the maximum price paid be limited to no more than 105 per cent of the average middle market closing price of BHP Billiton Plc's Ordinary Shares for the five dealing days preceding the date of purchase.