Papers concerning the Prince and Princess of Wales’s marriage are among those kept secret

Whitehall officials have been accused of covering up the past after they censored a record number of official documents due to have been made public.

Last year government departments applied to keep 7,406 documents from publication by the National Archives, an increase of more than 30 per cent.

Many of the papers date from the early years of John Major’s premiership. They include a Downing Street file on the marriage of the Prince and Princess of Wales as well as records on the Lockerbie bombing and the murder of Pat Finucane, a Belfast human-rights lawyer killed by loyalist paramilitaries allegedly in collusion with MI5.

Another concerns the reappointment of Jacques Delors as president of the European Commission. Mr Delors, who is now 93, was the