Gloucestershire MPs will decide tonight or whether Boris Johnson should be ousted as Prime Minister.

A vote of no confidence is due to be held between 6-8pm after 54 letters were submitted by Conservative MPs seeking his departure.

In a statement Graham Brady, the chair of the 1922 Committee that represents backbench Tories, said the 15 per cent threshold of MPs seeking a confidence vote "has been exceeded".

Forest of Dean MP Mark Harper submitted his letter in April  and led calls for Mr Johnson to quit.

He said the Conservative leader was "no longer worthy of the great office he holds" after he broke Covid laws.

All six of the Gloucestershire MPs are Conservative. So far only Mr Harper has spoken publicly about where his allegiance lies.

Gloucester MP Richard Graham tweeted earlier today: "I welcome any & all constituents mailing me your views on the VoteofNoConfidence this eve. As always your mail will be treated in confidence & I hope you will respect my right to privacy on private letters to 22 Cttee Chair & how I vote in a secret ballot."

Gloucestershire's other MPs are Alex Chalk (Cheltenham), Siobhan Baillie (Stroud), Sir Geoffrey Clifton-Brown (Cotswolds) and Laurence Robertson (Tewkesbury).

The vote will be held in person but as a secret ballot. Votes will be counted immediately after the ballot closes with the results announced at a "time to be advised" said Mr Brady's statement.

To stay in office, Mr Johnson needs to win the support of at least 50 per cent of all Tory MPs plus one, totalling 180. If he does win he is theoretically safe from such a challenge for a year - although the rules can be changed.

If he loses the vote the party will choose a new leader and thus a new prime minister.

The PM is due to address backbench MPs later today to rally support.

Foreign secretary, Liz Truss tweeted: "The prime minister has my 100% backing in today's vote and I strongly encourage colleagues to support him ... He has apologised for mistakes made. We must now focus on economic growth."

A No 10 spokesperson told the Guardian tonight was a chance to "end months of speculation and allow the government to draw a line and move on, delivering on the people's priorities".