The paper - understood to have been sent out by senior managers in charge of the system - predicts that more than 1,000
sub-post offices will be closed. During the same period, 717 main 'Crown' post offices will also be shut, the document indicates.
The Union of Communication Workers insisted at the TUC conference yesterday that the paper was dated 15 August, two months after the Government's Green Paper on the future of the industry.
Senior managers said, however, that the projections were made in May before ministers published a range of plans which envisage greater commercial freedom.
The favoured option of Michael Heseltine, President of the Board of Trade, is that 51 per cent of Parcelforce and the Royal Mail, with a total turnover of pounds 4.5bn, be sold off to the private sector.
Tory backbenchers have joined the UCW to express concern that privatisation plans would mean the closure of post offices, particularly in rural communities.
The memorandum also estimates that the number of 'franchised' offices would increase by 380 up to 1999. Many such operations are concentrated in supermarkets away from town centres and are inaccessible to the elderly and infirm, critics believe.
The row over the document comes ahead of a debate on the privatisation of the Post Office at the TUC tomorrow.
Under the options in the Government's consultative document, the counters division was to be separated from the rest of the operation. Alan Johnson, general secretary of the UCW, said the division would be given limited commercial freedom, but 'to suggest that the freedom on offer - welcome though it is - will save almost 2,500 post offices is not feasible'.
A Post Office spokesman described Mr Johnson's interpretation of the memorandum as 'absolute nonsense'. The network of offices was not at risk and management had gone to great lengths to ensure they remain open for the 28 million customers a week who use them. 'It is nonsense for the UCW to maintain the document represents the current position. Regrettably this is simply further scaremongering using out-of-date information out of context.'