A Suffolk MP has said he is "unhappy" with the prime minister over Covid rule-breaking but refused to say whether he has formally submitted a letter of no confidence.

Responding to around 300 letters from concerned constituents, Dr Dan Poulter, MP for Central Suffolk and North Ipswich, said PM Boris Johnson's "repeated assurances" to Parliament that there was no rule-breaking "lack credibility."

He wrote: "I am as unhappy as you are that people in very senior positions in both the Civil Service and in politics appear to have breached the very same rules they were making for others to follow.

"However, there is a much bigger issue at stake which is of trust and integrity in high public office.

"The most serious charge against the Prime Minister is that of knowingly misleading parliament. Given the scale of rule-breaking in No.10 and across Whitehall that has now been confirmed by the Sue Gray report, I find it difficult to accept that the Prime Minister was unaware.

"His repeated assurances in Parliament that there was no rule-breaking lack credibility."

"It is a matter of principle that a minister who knowingly misleads Parliament should resign and this principle should also apply to the Prime Minister. Whether or not the Prime Minister is an asset to the country is of less importance," he added.

Mr Poulter is the latest Suffolk MP to criticise the prime minister following the publication of Sue Gray's report into parties in Downing Street during the lockdowns.

Waveney MP Peter Aldous called for Boris Johnson to resign in February.

At the time, he said: "It is now my belief that the Prime Minister should resign.

"While I am conscious that others will disagree with me, I believe that this is in the best interests of the country, the government and the Conservative Party."

So far, 28 Tory MPs have openly called on the PM to resign.

A threshold of 54 letters of no confidence has to be reached in order for a vote of no confidence among Tories MPs to take place.