Former prime minister Boris Johnson is set to release a written dossier of evidence in his defence ahead of his grilling in front of the Privileges committee.

Mr Johnson will appear before the panel of seven MPs this week, who are seeking to decide whether he misled the Commons over claims about his knowledge of ‘Partygate’ gatherings in No 10 and Whitehall.

In an interim report, the Privileges Committee said it believes Mr Johnson “may have” misled Parliament, but it is seeking to understand whether this was intentional or inadvertent.

They are examining evidence around at least four occasions when he may have deliberately misled MPs with his assurances to the Commons that rules were followed.

When will Boris Johnson release his ‘dossier’ of written evidence?

According to reports by The Sunday Times, Mr Johnson has prepared a 50-page dossier alongside his lawyers which will be submitted to the committee this week.

It is understood to include previously undisclosed WhatsApp messages from senior civil servants and aides indicating he had relied upon their advice when he made his statements to Parliament.

A source familiar with Mr Johnson’s defence told the paper: “The messages will show in black and white that what Johnson told parliament was what he had been advised to say by officials and his No 10 team.

“The argument will be that it was reasonable for him to rest upon those assurances… What we are trying to show is that he said what he believed and was told at the time.”

Mr Johnson’s legal team must provide the 50-page dossier to the committee by Monday morning, and it is expected the full document will be made public prior to his evidence session on Wednesday.

When will Boris Johnson appear before the Privileges Committee?

Mr Johnson is set to give evidence in Parliament on the afternoon of Wednesday 22 March between 2pm and 6pm.

The grilling will take place in a committee room in the House of Commons, and the four-hour session can be watched online.

Who are the MPs who will be questioning Boris Johnson?

The seven-person committee questioning Mr Johnson is made up of four Conservative MPs, two Labour MPs and one SNP MP – representing the Conservative’s majority in Parliament.

The SNP’s MP on the committee is Allan Dorans. The two Labour MPs are Yvonne Fovargue and Harriet Harman, who is chairing the inquiry after the committee’s usual chair Chris Bryant recused himself from the process.

According to Commons rules, the Privileges Committee must be chaired by an MP from the official opposition.

Alberto Costa, Sir Bernard Jenkin, Andy Carter and Laura Farris – the four Conservative MPs on the panel – have faced pressure from grassroots Conservative members for their involvement, with some calling for them to denounce the committee.

The committee has been advised on legal matters during the inquiry by Sir Ernest Ryder, a former Court of Appeal judge.

What will happen during the televised evidence session?

Over the four-hour session on Wednesday, MPs will question Mr Johnson on statements he made to Parliament regarding the legality of activities in 10 Downing Street and the Cabinet Office under Covid regulations.

The investigation focuses on four statements when Mr Johnson appeared at Prime Minister’s Questions on 1 December and 8 December 2021, although the inquiry is not limited to these instances.

On the latter date, Mr Johnson told the Commons he had been “repeatedly assured that the rules were not broken” and insisted that “the guidance was followed and the rules were followed at all times” at events in Whitehall and Downing Street.

The committee is not drawing on the evidence set out in the ‘Partygate’ probe published last year by senior civil servant Sue Gray, and is said to instead be drawing on a cache of messages, emails and other documentary evidence far greater than Ms Gray obtained.

Mr Johnson will answer the questions on his own, but he has been supported in the preparation for the inquiry by a six-person legal team led by Lord Pannick KC.

It is expected that Lord Pannick will be in the room with Mr Johnson throughout the session, however, and will be able to pass him notes throughout.

The ex-PM reportedly plans to argue that he informed Parliament with the information he believed to be true at the time and that he ultimately corrected the record once he was provided with new information.

The committee has stated it will not be inviting any of the other 23 witnesses to provide oral evidence, but many have already provided written testimony under oath.

It is currently unclear whether Mr Johnson will be called again to give evidence to the committee following Wednesday’s session.

What sanctions could the Privileges Committee impose on Boris Johnson?

Following the evidence session, the committee is expected to take several weeks to deliberate before it reaches a decision on whether Mr Johnson misled Parliament.

The committee has the power to impose a number of possible sanctions including an oral or written apology, suspension from the House for a limited time, or expulsion from the House.

If the committee decides Mr Johnson has misled Parliament and imposes a sanction, it must be voted on by the whole House.

Any recommended suspension of more than 10 sitting days would automatically trigger a recall petition in Mr Johnson’s constituency, which could trigger a by-election if 10 per cent of eligible voters in the constituency sign it.

Will MPs get to vote on any sanctions?

Once the committee has finalised its report, any recommended sanction must be voted on by the whole House without debate.

It is the convention that this is a free vote, meaning MPs are not required to vote in line with their party.

In the case of sanctions against Owen Paterson, however, the government instructed MPs to oppose the recommended penalty, leading to widespread backlash.

Prime Minister Rishi Sunak has indicated he would not whip any vote regarding sanctions against Mr Johnson, claiming such a move “wouldn’t be right” as it is “not a matter for the Government”.

A number of Mr Johnson’s supporters have already indicated they will vote against any sanction put forward by the Privileges Committee, branding the inquiry a “witch hunt”.