Work started today to clear the massive backlog of mail after a six-day strike ended.

But union bosses and the Royal Mail are refusing to release details of the agreement reached over the suspension of a Bicester postman accused of harassment.

Both sides would only say the agreement was acceptable to all parties, including the suspended worker, but would not say if he had been reinstated, although it is believed he has been. Royal Mail spokesman Richard Hill apologised for the inconvenience. He said: "Our aim is to get through the backlog as quickly as possible but at this stage it's impossible to say how long that will take us."

About 700 staff from Oxford and Bicester had walked out at the height of the dispute.

But after an agreement was reached at 5.30pm last night, some went straight back to work and post boxes had seals removed. Pete Boswell, secretary of the Oxfordshire branch of the Communication Workers' Union, said: "It's exam result week and we know important housing benefit cheques are also in the post. Workers will now pull out all the stops to get the mail out and clear up the backlog."

Staff at Bicester walked out over the suspension of the postman, who is in his 40s, and were supported by their city colleagues.

It had earlier been revealed the alleged victim of the harassment was also out on strike in support of his colleague.

The two were said to have made up a month ago but the worker was still suspended after a boss decided to launch an official investigation.