Theresa May has said Britain "will leave" the EU in March 2019, amid concerns from a Tory backbencher that Brexit talks could be extended.

The Prime Minister also suggested the UK's role in the EU's common fisheries policy would have to be negotiated during any transition period.

At Prime Minister's Questions, Eurosceptic Tory Peter Bone called on the Prime Minister to give an assurance "that under no circumstances will the negotiations be extended".

Mrs May responded that Article 50 did allow for an extension of exit negotiations, adding: "I've been very clear.

"We want those negotiations to end - not just the negotiations to end, we want to have an agreement on the future relationship, and our withdrawal - by March 2019, and we will leave the EU on March 2019."

Environment Secretary Michael Gove is said to be pushing for the UK to leave the fisheries policy immediately after Brexit, and not remain in it through any transition.

Liberal Democrat Alistair Carmichael, a former Scottish secretary, raised the issue during the questions session.

"When we have left the European Union, we will be leaving the common fisheries policy," Mrs May said.

"As part of the agreement that we need to enter into for the implementation period, obviously this and other issues will be part of that agreement.

"But when we leave the European Union, we will leave the common fisheries policy."

Earlier, shadow Cabinet Office minister Jon Trickett attacked the Government over a perceived failure to prepare for a "no deal" scenario if the UK fails to agree a new trading relationship with Brussels.

It comes after Chancellor Philip Hammond suggested that taxpayers' money should not be used for preparing for such an outcome from the negotiations, saying he would only spend the cash "when it is responsible to do so".

Speaking at Cabinet Office questions, Mr Trickett said: "The truth is there is no contingency plan for a 'no deal' Brexit and that explains the breakdown of policy co-ordination which he is supposedly responsible for right at the heart of Government.

"This Government is a shambles: it's wholly divided.

"After all we had a Prime Minister who said no deal is better than a bad deal, a Chancellor who now said he won't fund a no deal scenario, and a Foreign Secretary who seems perfectly happily with no deal arrangement.

"The stakes cannot be higher, but the Government is a shambles."

First Secretary of State Damian Green urged Mr Trickett to read what the Chancellor said, adding: "I am happy to assure him and the House that yes, the Government is preparing for all eventualities as a responsible Government would."

He went on: "Of course what this Government is working hard to do is to make sure that we get the best Brexit deal for this country that will ensure the future prosperity of this country for decades to come."