Theresa May's Brexit policy could be "in tatters" after she appointed to the Government a prominent Eurosceptic MP who tried to block a transition deal, Labour has claimed.

The Fareham MP has risen swiftly through the ranks after only being elected to Parliament in 2015 but her appointment has drawn controversy over her staunch Eurosceptic views.

Last year, Ms Fernandes coordinated a letter from some 40 Tory MPs opposing staying in the single market as part of the transitional deal with the European Union, a move they described as staying in the EU "by stealth".

The remarks are at odds with the Government's position, as Ms May backed a transitional deal in a major speech in Florence last year.

Shadow Brexit Minister Paul Blomfield, who has written to Ms Fernandes on the matter, said: “The appointment of Suella Fernandes has left the Government’s Brexit policy in tatters.

“Her previous comments demonstrate that she has no interest in securing a transitional deal with the European Union and in fact actively sought to undermine the Prime Minister’s own negotiating position. She should retract her earlier remarks or step aside.”

The EU's guidelines on transitional arrangements say that existing rules and regulations would remain the same during any transition period, as the UK was still a member state.

The position sits uneasily with Eurosceptic MPs who favour a hard Brexit and have tried to put pressure on the Government to walk away rather than cave to EU demands.

She said: “In the event of ‘no deal’ that’s great as well for us. The ideal is a free trade agreement but in the event of that not working, ‘no deal’ is something we will capitalise on using our strengths and the opportunities that brings.”

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It comes as a group of cross-party MPs launched a bid to change the Government's flagship Brexit legislation when it returns to the Commons next week.

SNP, Green, Liberal Democrat and Plaid Cymru MPs have tabled an amendment to the EU (Withdrawal) Bill that would stop ministers from using sweeping powers to take the UK out of the single market and the customs union after Brexit.

Labour has also tabled a separate amendment calling for the UK to remain in the Single Market and a Customs Union with the EU during a time-limited transition.

A DExEU spokesperson said: "Suella Fernandes has an excellent track record both as a barrister and as an MP, and brings with her a thorough understanding of both the EU and the Brexit negotiations.

“She is joining a team that is committed to securing a smooth transition out of the EU. That is why we are proposing a simple, clear and time-limited period of implementation - using the existing structure of EU rules and regulations - that is in the interests of the whole of the UK and the EU.

"We want to reach agreement on the implementation period as soon as possible in order to provide certainty for businesses and people.