Edward VIII was secretly bugged during the final days before his abdication on the order of his own ministers, according to official files made public yesterday.

Papers held secret in the Cabinet Office for more than seven decades show Home Secretary Sir John Simon instructed the General Post Office (GPO) covertly to monitor the King's telephone calls.

It suggests a breakdown of trust between Edward and his ministers as he wrestled with his decision whether he should give up his throne or the woman he loved.

It was against this backdrop Sir John instructed the GPO to intercept his calls. The files released by the National Archives in Kew, west London, include the draft of a note sent from the Home Office to the head of the GPO, Sir Thomas Gardiner, confirming Sir John's order.

It stated: "You will arrange for the interception of telephone communications between Fort Belvedere and Buckingham Palace on the one hand and the Continent of Europe on the other."