A further 4,000 post offices could close on top of the 2,500 already ear-marked for closure, a group of MPs have warned.

The Post Office had not set a minimum number of outlets for closure and subpostmasters might not be replaced if they were to retire, said the Business and Enterprise Select Committee.

"We do not think it is satisfactory simply to accept that the network may continue to shrink in an unplanned way between now and 2011,”| said committee chairman Peter Luff.