Michael Howard has urged the Home Office to release key documents relating to his time in charge of the department.

In a letter to permanent secretary Sir John Gieve, the Conservative leader said papers relating to five key events should now be made public.

The move followed a wave of controversy over the release of Treasury documents on the impact of Black Wednesday, when Sterling crashed out of the European Exchange Rate Mechanism.

Howard, who was home secretary from 1993 to 1997, said that the papers should be released "in the interests of openness".

"Over the last month, a number of issues relating to my time as home secretary have been raised," he wrote.

"Requests have also been submitted under the Freedom of Information Act.

"I believe in openness. I, therefore, want this information to be made public."

He called for the immediate release of information on Mohammed Al Fayed's request for UK citizenship - which was turned down.
 
Further papers that Howard said should be made public include details on the breakout from Parkhurst prison in 1995.

Others relate to the passport application of Petronella Wyatt, a Spectator journalist whose request may have been fast-tracked but where Howard denies any wrong-doing, and the decision to authorise a royal pardon for two drug smugglers.

The final set of papers relates to the departure of Derek Lewis from his post as director general of the Prison Service in 1995.

Famously, the departure led to Newsnight presenter Jeremy Paxman asking Howard 14 times if Lewis had been made a scapegoat.

"I would like all relevant papers to be published," Howard wrote.

Officials said the Conservative leader was seeking to prove that he had nothing to hide.

The move could also avoid any accusations that he is seeking to block the release of embarrassing information.

Former prime minister John Major accused Labour of dirty tricks in suggesting he sought to block the release of the ERM papers when he had no objection to their release.