I apologise for changing my mind. Theresa May’s deal is a bad one, it does not deliver on the promises made in the Tory Party manifesto and its negotiation was a failure of statesmanship.

A £39 billion bill for nothing, a minimum of 21 months of vassalage, the continued involvement of the European Court and, worst of all, a backstop with no end date.

Yet, I am now willing to support it if the Democratic Unionist Party does, and by doing so will be accused of infirmity of purpose by some and treachery by others.

I have come to this view because the numbers in Parliament make it clear that all the other potential outcomes are worse and an awkward reality needs to be faced.

Mrs May ought to have concluded a better agreement but behind the backs of two secretaries of state, David Davis and Dominic Raab, she did not.

The agreement on the table is as it is, and the proposal to replace the backstop with something else, particularly the Malthouse Compromise (a managed No Deal exit — if a deal cannot be agreed) has floundered.

Jacob Rees-Mogg has said he is ready to back Theresa May's deal 'because the numbers in Parliament make it clear that all the other potential outcomes are worse'

Delay

The EU, in the knowledge that it was dealing with a weak counterparty, has refused to reopen the text and the Government has not been willing to threaten No Deal in any effective way. The late start to No Deal planning and the reluctance to use it in negotiations has been a significant reason for the poor outcome.

Until last week, nonetheless, No Deal remained the default legal option but the Government and the Prime Minister have now ruled this out and with the support of Parliament can now do so.

No Deal is an outcome I would prefer to Mrs May’s deal. It would be a fully-leaded Brexit and mere motions in the Commons could not have stopped it.

Indeed, despite a clear majority of MPs opposing such a departure, it would have happened on Friday had Mrs May not used her executive authority as Prime Minister to postpone the day of Brexit.

Once No Deal had been ruled out, it was necessary to examine what would happen in the event of the current agreement not passing. This would lead to a long delay as there is no opportunity of renegotiating anything before the European elections at the end of May. Two years or more is proposed but considering the opposition to Brexit it could be revoked or put to a skewed second referendum.

A long delay would make remaining in the EU the most likely outcome.

If the moral authority of 17.4 million voters and a General Election in 2017 when both main parties committed to respecting the result could not deliver our departure in three years, how strong a mandate would it be after five? Even if the fear of remaining were exaggerated, it would inevitably lead to an even softer Brexit.

It is a sad fact that there is a gulf between Parliament and the people. Fifty-two per cent voted Leave but two-thirds of MPs want to remain. The Lords is even worse with a tiny minority of pro-Leave peers.

After giving people the right to decide, too many politicians felt that the voters gave the wrong answer and must be saved from themselves. Two years further from the referendum would allow for the demands to be watered down again, leaving the UK shackled by a Customs Union or as a Norway-style rule-taker.

If this were all, it could be sensible to take the risk and see if something better turned up. A number of Tory MPs think a new leader could swiftly renegotiate but that is almost certainly not true now that Parliament has taken control of the Brexit timetable.

No Deal is an outcome I would prefer to Mrs May’s deal. It would be a fully-leaded Brexit and mere motions in the Commons could not have stopped it.

It would be even harder for a Eurosceptic to manage the current Commons than it is for Mrs May. Even if this could happen, politicians must look at the current constitutional clash and fear for our polity.

The constitution is under attack in three ways. The first is between the Government and the Commons.

This has been encouraged by the Speaker whose noble efforts to allow the Commons to hold the Government to account have gone too far and now seek to take the role of the Government to the legislature.

Recklessness

This is dangerous because the Commons’ job is to provide confidence in a Prime Minister who can take decisions for which she or he is accountable.

These decisions ought to be in accordance with manifesto commitments and if there is no confidence in the duly elected Prime Minister, then control ought to return to voters, not to a cabal of MPs who will have random majorities on various issues but no clear leader or mandate.

Separation of powers between Downing Street and the Commons is a crucial part of how we are ruled and a protection against arbitrary government.

Upsetting this balance is unwise to the point of recklessness and the Sir Oliver Letwin takeover proves the point.

Unfortunately, the second breakdown is just as serious. The Government only functions if ministers support a single position or resign, and this has been the reality since the 1830s. There can only be one Government position, otherwise how can it be held to account? How can electors know how power is being exercised if different ministers say the first thing that pops into their heads?

Recently, three Cabinet Ministers failed to back Government policy on the vote to leave the EU without a deal and in a rather jejune fashion ostentatiously abstained.

As they did not resign, this undermines one of the cornerstones of the constitution, making it harder for the Government to function.

Faltering

Any government must be able to get its business done. If it cannot, it is unable to govern. The principle of the separation of powers and of collective responsibility lie at the heart of this.

A number of Tory MPs think a new leader could swiftly renegotiate but that is almost certainly not true now that Parliament has taken control of the Brexit timetable

The great Duke of Wellington was famous for insisting that the Queen’s Government must go on and that all responsible politicians have a duty towards such an end, even if it countermands their own piety.

The worst breakdown, though, is between the elected and the electors.

The condescension of politicians who feel that Leave voters were all stupid and ought never to have been allowed to decide something so complicated is tragic.

Ultimately, voters know best and must be trusted. Imperfect as it is, Mrs May’s deal gets closer to that than anything else available.

The Withdrawal Agreement has one great virtue. Legally, we would have left and to re-join would mean agreeing to adopt the Euro single currency, Schengen (the abolition of national borders) and no rebate. Such a course would be expensive and hugely unpopular.

The backstop, too, could tie us into rules that we did not like. But outside the EU, it would be a political not a legal matter.

International law is not as clear-cut as EU or domestic law and there is no court to rule between states and international bodies.

Ultimately, Brexit could be delivered upon but it would take longer.

It would need a Commons that wants to use our freedoms and that is willing to insist that the word ‘temporary’, as applied to the backstop, is genuine.

It needs political leadership and a desire to stop the weak-minded managing of decline and a belief in the UK.

Theresa May’s deal is a more faltering step than I want, or feel, could be taken —but at least it is a step forward.