Who is the Speaker of the House of Commons and what do they do?

The future of the Speaker of the House of Commons, Sir Lindsay Hoyle, is under threat, after a Gaza-ceasefire debate descended into chaos.

Dozens of MPs have called for his resignation.

Sir Lindsay Hoyle was elected as Speaker on 4 November 2019, following the resignation of the previous Speaker, John Bercow.

Sir Lindsay was originally elected to Parliament as Labour MP for Chorley, Lancs, but the role of the Speaker is politically impartial.

Incoming Speakers resign from their party when appointed and typically stand unopposed in general elections held during their term in office. They can still undertake work on behalf of their constituents.

The modern Speaker has a number of important duties:

The Speaker works closely with the Clerk of the House of Commons, who advises on parliamentary procedure and constitutional matters.

Former Conservative MP Eleanor Laing is the main deputy Speaker, and can perform all of the Speaker's duties in his absence.

Sir Lindsay was accused of "playing party politics" by going against the usual parliamentary convention, to allow a vote on a Labour motion for an "immediate humanitarian ceasefire" in Gaza.

Wednesday had been designated an SNP opposition day in the Commons.

Normally, the nominated opposition party - in this case the Scottish National Party - proposes a motion for debate. And typically only the government is allowed to suggest amendments to an opposition motion.

But Sir Lindsay decided to let MPs vote on a Labour amendment.

He said this was so MPs could express their view on "the widest range of propositions" - but critics say he let Labour hijack the Gaza debate.

The move meant Labour MPs could call for a ceasefire, without backing the differently worded SNP motion, which could have split the party.

A number of SNP and Conservative MPs walked out of the Commons chamber in protest.

Sir Lindsay later apologised but more than 50 MPs have called for his resignation.

The Speaker is elected by a secret ballot of MPs at the beginning of a new Parliament after a general election - or following the death or retirement of their predecessor.

If the Speaker wishes to continue in their post after a general election, they do not need to be re-elected by secret ballot and can instead be reappointed if a majority of MPs vote in their favour.

There is no formal mechanism for MPs to oust the Speaker from their role.

Erskine May, the "bible" of parliamentary procedure, explains that once elected, the Speaker "continues in that office during the whole Parliament, unless in the meantime they resign or are removed by death".

MPs can criticise the Speaker by putting down a motion against them. And the government of the day can provide time for it to be debated on the floor of the House.

But there is a precedent for a Speaker being pressurised into a resignation.

Michael Martin, who served in the role from 2000 to 2009, stepped down after criticism of his handling of the MPs' expenses scandal.

He said he wanted to maintain the unity of the House of Commons.

The first female Speaker, Betty Boothroyd, spent more than 20 years in the Lords, until her death in 2023.

Elected as the Labour MP for West Bromwich West in 1973, Baroness Boothroyd served as Speaker between 1992 and 2000.

Mr Bercow had been accused of bullying by his former colleagues.

He told BBC Radio 4's Any Questions he had "made a lot of enemies" during his 10-year stint in the Commons, but denied he had bullied anyone.