Commons Speaker Sir Lindsay Hoyle was branded a “publicity-mad loony” for fuelling conspiracy theories about the death of Princess Diana, according to newly released official files.

In the summer of 1998, Mr Hoyle (as he then was) sought to press Tony Blair over the supposed involvement of “British security agents” in Paris on the night the previous year when Diana and her lover, Dodi Fayed, were killed in a car crash.

However papers released by the National Archives, show that his calls for a public statement drew a withering response from the Prime Minister, who dismissed the claims as “ridiculous and deeply distressing” to the princess’s family.

Mr Hoyle wrote to Mr Blair urging him to “clear up some of the secrecy and controversies” surrounding Diana’s death after his attempts to table written questions in the Commons were blocked by the House authorities.

“There has been an enormous amount of speculation on recent television documentaries that somehow British security forces may have been involved in the death of Diana,” he wrote.

Lancashire Telegraph: Pictured, former Prime Minister Tony Blair. Photo via PA.Pictured, former Prime Minister Tony Blair. Photo via PA.

“Making a statement on this matter would answer many of these questions and put an end to these rumours and uncertainty.”

Mr Hoyle had only been elected as Labour MP for Chorley in 1997, but had already attracted headlines after calling for a new national children’s hospital to be built as a memorial to Diana, and for Heathrow to be renamed Diana, Princess of Wales Airport.

Following his latest intervention, one No. 10 official scrawled in a handwritten note: “Lindsay Hoyle is publicity-mad loony.”

The Foreign Office drew up a suitably “dismissive and definitive” reply for Mr Blair to send to the MP, although officials suggested it may be better for the chief whip Nick Brown to speak to him instead.

“Mr Hoyle is likely to relay whatever he receives to the media,” John Grant, the principal private secretary, informed No 10.

“Our news department believe that a written statement coming ‘out of the blue’ could end up giving the story a fresh wind and encourage the press to recycle all the conspiracy theories of linkage between the agencies and the accident before printing the Prime Minister’s denials.

“Their preference would be to avoid putting anything in writing if we can.”

However Mr Blair’s chief of staff, Jonathan Powell, said that was “daft”, adding “much better to put this in writing clearly and dismissively”.

In his letter to Mr Hoyle, marked “personal”, Mr Blair said it would “inappropriate” for him to make any sort of statement that might prejudge the ongoing French investigation into the crash.

He added: “However, as the Foreign and Commonwealth Office have been saying for months, any suggestion that any British official organisation or department had anything to do with this tragic event is both ridiculous and deeply distressing for the bereaved families.”