John Bercow has defended allowing a controversial amendment to be tabled on the government's Brexit bill - saying "I'm trying to do the right thing".

The Commons Speaker and Bucks MP faced a backlash from Conservative MPs for selecting the motion from former Attorney General Dominic Grieve, Beaconsfield's MP, which would force the Prime Minister to come back to the House with a revised EU exit plan within just three days of her losing the vote next week.

After it was suggested the Government's motion was "unamendable", Mr Bercow told the Chamber: "My understanding is the motion is amendable, I'm clear in my mind about that."

After heckles from the Tory benches, he added: "I'm trying to do the right thing and make the right judgements. That is what I have tried to do and what I will go on doing."

The row came after a point of order from senior Tory backbencher Peter Bone (Wellingborough), who said he was told by Commons authorities that such a motion would be "totally out of order".

But Mr Bercow said that his understanding was not the case, which sparked a flurry of other points of order on the same subject.

Tory Eddie Hughes (Walsall North) asked "I wonder, Mr Speaker, if you could point me towards the precedent that would allow for what seems to be an unamendable motion to be amended so I can be informed?"

Mr Bercow said he was not in the business of "invoking precedent", adding that: "It is the long-established practice of this house that the Speaker in the chair makes judgements on the selection of amendments, and those judgements are not questioned by members of the House.

"I am clear in my mind that I have taken the right course."

Deputy chairman of the ERG Mark Francois claimed Mr Bercow was not following his own rules.

Raising a point of order after PMQs, the Tory MP for Rayleigh and Wickford quoted the original business motion, which said: "No motion to vary or supplement the provisions of this order shall be made except by a Minister of the Crown and the question on any such motion shall be put forthwith."

He continued: "Mr Speaker, I have not been in this House as long as you but I have been here for 18 years and I have never known any occasion when any Speaker has overruled a motion of the House of Commons.

"You have said again and again you're a servant of this House and we take you at your word, and I have heard you many times on points of order when people have challenged you say 'I cannot do X or Y because I am bound by a motion of the House'.

"You have done that multiple times in my experience, so why are you overruling this today?"

As a furious Mr Francois yelled "ridiculous" and "that is utter sophistry", Mr Bercow defended his decision.

"The answer is simple," he said. "He referred to a motion and he said that no motion in this context, for the purposes of precis, may be moved other then by a Minister of the Crown. Tis so.

"We're not speaking here of a motion but of an amendment to a motion. I'm sorry but there is a distinction between a motion and an amendment.

"What he says about a motion I accept but it doesn't relate to an amendment. That is the answer."

Commons Leader Andrea Leadsom noted there were "some concerns" about Mr Bercow's decision and asked him to confirm that his decision was taken with "full advice" from the Commons clerk and other parliamentary advisers.

She asked him to publish the advice, which prompted cheers from Tory MPs.

Mr Bercow confirmed he consulted the clerk and officials, saying the advice was given to him "privately and that's absolutely proper".

He said: "It's also true I had a written note from the clerk from which I quoted in responding to the first point of order."

Tory MP David Morris (Morecambe and Lunesdale) leapt to his feet and repeatedly shouted: "Publish it!"

Mr Bercow added there was not full written advice nor a brief, but did not confirm that his decision was taken with agreement from the Commons clerk Sir David Natzler.

Conservative former cabinet minister Ken Clarke earlier said he found it "unbelievable" that some MPs were trying to stop the Commons expressing its opinion on the matter.

He said: "I would suggest to some of my honourable friends - the ones that are getting somewhat overexcited - that perhaps they should don a yellow jacket and go outside."

Tory MP Heidi Allen (South Cambridgeshire), also raising a point of order, said: "I am absolutely hopping mad.

"When I became an MP three years ago I was determined that I would not become part of the establishment. Do people in this House have any idea how out-of-touch the general public think we are most days?

"We are talking about 79 days until potentially crashing out of Europe without a deal - should our focus not be on the detail and the arguments about the process in this place, but getting on with a plan B if Parliament decides the Government's plan is not the one for the people?

"When are we going to start acting like public servants doing the right thing and having the debate and getting on with it?"

Asking a further point of order, Tory former cabinet minister Iain Duncan Smith asked if the Speaker's decision had set a precedent.

He said that he had previously - particularly during the Maastricht debates - requested from the clerks whether or not MPs could amend business motions and was always "told categorically that precedent said that was not possible".

He asked: "Will the instruction go to the clerks that in future a backbencher wishing to amend a forthwith motion will now allow and be accepted against any business at all in this House?"

Mr Bercow replied: "It seems entirely reasonable for me to say to him that I would like to reflect on that matter."

He added: "If we were guided only by precedent manifestly nothing in our procedures would ever change."

Raising a further point of order, Tory Sir Christopher Chope (Christchurch) addressed Mr Bercow stating: "Let nobody suggest that you by your actions have been undermining Brexit.

"Can I also say that it seems to me absolutely an own goal for this House if we start undermining your position in the chair?"

Mr Bercow replied: "The fact is there is a responsibility upon the chair to do its best to stand up for the rights of the House of Commons including the views of dissenters on the Government benches ... and to defend the rights of opposition and very small parties as well."

Jacob Rees-Mogg queried whether the motion, if altered by Mr Grieve's amendment, had to be accepted by the Government, as his reading of the rules was that any motion had to be put to a final vote by a minister.

The Tory MP for North West Somerset asked: "Is it therefore the case that the motion, if amended, may not then be put unless it is adopted by a Minister of the Crown?"

Mr Bercow replied: "The answer is that if the motion has been moved it must then be put, and for the avoidance of doubt I say that on the basis of specialist advice."

Tory MP Adam Holloway (Gravesham) later accused Mr Bercow of having a "derogatory" sticker about Brexit in his car.

He said: "We've all noticed in recent months a sticker in your car making derogatory comments about Brexit. Have you driven that car with the sticker on?"

Mr Bercow said that was a "factual error" and told MPs the car belonged to his wife.

He said: "That sticker on the subject of Brexit happens to be affixed to or in the windscreen of my wife's car, and I'm sure he wouldn't suggest for one moment that a wife is somehow the property or chattel of her husband. She is entitled to her views, that sticker is not mine and that's the end of it."

Mr Bercow's comment drew huge cheers and applause from Labour and SNP MPs.

MPs approved Tory former minister Dominic Grieve's amendment by 308 votes to 297, majority 11.