Computers containing research, future plans and the names and address of CND members and Parliamentary contacts were taken from offices on Holloway Road, in north London, over one weekend in April.

But other valuable goods were not touched, said a CND official.

He said: "The police commented that the break-in was very suspicious and unusual in its execution, not like any normal burglary they attended."

The organisation, which opposed the war in Iraq, said it had a back-up of most of the information contained on the stolen computers.