Northern Rock, the stricken British lender, could still owe the Bank of England billions of pounds in three years' time, according to a confidential sales memo circulated to would-be buyers.

The memorandum, obtained by the Financial Times' Alphaville website, is now the subject of a court injunction after Northern Rock sought to prevent publication of its details. The High Court granted a limited injunction preventing further reporting of material published exclusively by the FT, but it rejected a much more sweeping prohibition sought by Northern Rock after much of the content was reported in other media.