The day the blue skies nearly fell in on John Birt

As the Prime Minister's strategy advisor, Lord Birt is supposed to come up with radical solutions for the future of government. But his blue sky thinking has been interrupted by a much more down-to-earth proposal for his boss - let's get the roof fixed.

A leaked memo reveals that the ceiling in Lord Birt's Downing Street office fell down recently - but to the probable dismay of many former employees, the former BBC director general was not in his room at the time.

"The ceiling in John Birt's room collapsed overnight," Jay Jayasundra, an accommodation manager at No 10 wrote in the internal memo. "Fortunately the room was empty at the time; had he been in the room he would have sustained serious injury."

The memo, seen by the Financial Times, did not mention exactly when the incident took place, but it seems the planned £30m refurbishment of Downing Street revealed in newspaper reports at the weekend cannot come soon enough.

After President George Bush's visit to London in 2003, Whitehall officials drew up plans for a £30m refit of No 10 - which has been home to prime ministers since 1732 - and adjoining buildings. Project George, as the proposal is called followed behind-the-scenes complaints from Mr Bush about security, "sewage smells", "poor" lighting and "non-existent" air conditioning. It is reported to be under consideration. But the Prime Minister would have to vacate the premises for two years.

A Downing Street spokesman said last night: "From time to time, with buildings of this age, these things do happen."