North Shropshire MP Owen Paterson has stated that Prime Minister Theresa May's 'betrayal' of the 2016 European Union referendum is why he has submitted a letter of no confidence in her.

Mr Paterson sent his letter to head of the 1922 Committee, Sir Graham Brady, on Tuesday evening, helping to trigger the vote of no confidence in the PM which will be held on Wednesday night.

Should Mrs May lose the vote, it will start a leadership campaign and will more than likely see her departure from Number 10 in the middle of her disastrous Brexit negotiations.

In his letter, Mr Paterson criticised Mrs May's 'lack of preparation' for a no-deal Brexit and her manner in trying to drum up support within government.

He said: "Dear Sir Graham,

I write to inform you that I no longer have confidence in the prime minister. It would be a travesty if the democratic verdict of the 2016 referendum – the largest in British history – were not delivered, yet the prime minister's proposed "deal" is so bad that it cannot be considered anything other than a betrayal of clear manifesto promises.

These broken promises typify more than two years of poor government decision-making. It was a mistake not to begin intense preparations for leaving on WTO terms the moment the result was delivered, approaching the negotiations with a stronger hand, positioned to walk away without a deal and consequently much more likely to secure a good one.

It was a mistake for our EU negotiations to be led by a career civil servant with no business experience when the government had on hand a vastly experienced international trade negotiator, Crawford Falconer.

It was a mistake to create a new Brexit department only to keep two secretaries of state so in the dark that they had to resign over a policy one would have thought they were overseeing.

Trying to bounce cabinet ministers into supporting her white paper on the future relationship before they had a chance to consider it fully – as the prime minister did at Chequers – is simply an intolerable way for a prime minister to govern.

It was a mistake to treat Brexit miserably as a problem to be solved rather than an exciting opportunity to be grasped. The UK is the world's fifth largest economy. We are a key NATO member, a permanent UN Security Council member, a Commonwealth realm, a nuclear power.

We are the source of the English language, the common law and occupy the ideal time-zone for global trade. Yet from the outset we have approached these negotiations as a feeble and unworthy supplicant. As Falconer said, future historians will ask in exasperation: "Why were we so negative about our future?"

These mistakes have eroded trust in the government, to the point where I and many others can no longer take the prime minister at her word. Almost two dozen times, she has ruled out membership of the customs union, yet the withdrawal agreement's "single customs territory" sees us locked into it in all but name.

She has repeatedly said "no deal is better than a bad deal", but it is clear her objective was to secure a deal at any cost.

The backstop would see the whole UK remain in a customs union with the EU, with Northern Ireland in the customs union and single market. This could see new internal UK borders in breach of the Belfast Agreement's principle of consent and the requirement to consult the Northern Ireland Assembly.

It breaches the Acts of Union 1800. The UK would not have the unilateral right to end the arrangement. We could be locked into it indefinitely as a permanent rule-taker while paying £39bn for the privilege.

European customs experts regard the withdrawal agreement's customs arrangements as woefully out of date, proposing physical stamps and paper systems not used for nearly 20 years. They are so vague that it would be impossible to put them into practice.

Eleventh-hour "reassurances" on this issue are mere warm words if the legal text is unchanged. In any case, there is much more besides the backstop making the withdrawal agreement unacceptable.

No amount of tinkering will yield a majority in parliament for this deal. The government needs to consider more boldly the possible alternatives which might command that support. President Tusk offered just such an alternative in March: a wide-ranging, zero-tariff free trade agreement.

That deal foundered on the question of the Northern Ireland border, but existing techniques and processes can resolve this. From my October meeting with Michel Barnier, I know that a willingness exists on the EU side to explore these possibilities more fully. The meeting also confirmed that Tusk's offer is still on the table.

Throughout this process, I have sought to support the government. The conclusion is now inescapable that the prime minister is the blockage to the wide-ranging free trade agreement offered by Tusk which would be in the best interests of the country and command the support of parliament.

I, therefore, have no confidence in Theresa May as prime minister and leader of the Conservative Party and ask that you hold a vote of no confidence."