A POST Office safe proved so secure it took a crack team seven days to work out how to open it.

Staff at the post office in Sedgefield, County Durham, called in the experts when they were unable to unlock the safe.

Three members of staff tried, and failed, to open the safe and, because there is no override system, there was nothing for it but to call in the professionals.

The team, reputed to be among the best safe engineers in the country, arrived on a Monday morning and started drilling in order to look inside and identify the problem.

But it proved to be trickier than anticipated. The engineers worked round the clock for the next week before finally solving the problem.

Sub-postmaster Basil Watson said staff, customers and the safe engineers were quick to see the funny side. "We got a lot of comments," he said,

"People were asking me 'Have you lost your key Basil?'. One person suggested getting some gelignite and others suggested asking the governor of Durham Jail to lend us one of his inmates."

The post office was provided with two replacement safes while the operation was being carried out, which finally ended in success.

Mr Watson said: "There was a lot of humour, but the whole episode proved that it is not a casual affair getting into that particular type of safe. It is much more complicated than anyone would believe.

"This problem demonstrates just how well the Post Office and its safes are protected."