A Conservative MP is hoping to increase pressure on Commons Speaker John Bercow by tabling a no-confidence motion.

Mr Bercow said this week he would be "strongly opposed" to US President Donald Trump addressing Parliament, accusing him of "racism and sexism".

James Duddridge said Mr Bercow had "overstepped the mark" although he did not expect his motion to be debated.

The Speaker is the highest authority of the House of Commons and is expected to remain politically impartial.

Who is John Bercow?

Mr Duddridge told the BBC: "I've done this because Speaker Bercow for a long time has been overstepping the mark and with his comments on the state visit [of President Trump] he has clearly expressed views.

"That is not the role of the Speaker, and it is impossible for him to chair debates as Speaker adjudicating on things he has expressed a view on.

"I've tabled a motion to the House of Commons. I expect over the week of recess for people to be supporting that but they can't actually sign it until the first day back.

Image copyright Getty Images Image caption Donald Trump was invited to make a state visit to the UK after Theresa May's trip to Washington

"But to be frank, I think there's a very real possibility that once the level of discontent is known and Speaker Bercow sees the writing is on the wall he will go of his own accord."

BBC Parliamentary correspondent Mark D'Arcy said other senior backbenchers doubt that Mr Duddridge's tactics would work.

He said Mr Bercow has a reservoir of support on the backbenches - particularly among pro-Brexit Conservative backbenchers - and was seen to have enabled MPs to challenge the government far more effectively.

Mr Duddridge, Conservative MP for Rochford and Southend East, had already written to the prime minister, asking for MPs to be given a free vote if there was a vote of no confidence in the Speaker.

Position 'untenable'

Conservative MP Alec Shelbrooke tweeted on Thursday that he disagreed with President Trump's executive order barring migrants from seven countries but added: "John Bercow has politicised the office of Speaker and his position is untenable."

But fellow Conservative Claire Perry said on BBC One's Question Time: "I think for us to try and remove a speaker over something that he said would be really rather drastic. He's entitled to his opinions, perhaps he just shouldn't have addressed them on this particular issue."

Meanwhile an early day motion calling for officials to withhold permission for Mr Trump to address Parliament, has now been signed by 204 MPs - largely from the Labour Party.

That motion was sponsored by the Labour MP Stephen Doughty - whose point of order about it on Monday prompted Mr Bercow's initial comments.

President Trump has accepted an invitation from the Queen for a state visit to the UK, which can include an address to both Houses of Parliament, later this year.

However, responding to a point of order in the Commons on Monday, Mr Bercow said he was opposed to Mr Trump speaking to MPs and peers saying it was "not an automatic right", but an "earned honour", to applause from Labour and SNP MPs.

He has since said it was time "to move on to other matters".

In March 2015 a bid to change the rules on electing Commons speakers - which was seen by some as a bid by the Tory leadership to oust Mr Bercow - was defeated by 228 votes to 202.

Mr Bercow is one of three "key holders" to Westminster Hall - where Mr Trump's predecessor Barack Obama spoke in 2011 - along with the Speaker of the House of Lords, Lord Fowler, and the Lord Great Chamberlain, a hereditary peer in charge of certain parts of the Palace of Westminster.

All three must agree in order for an address to take place there.

No date for Mr Trump's visit has been announced.