​I hope we will hear from the Supreme Court on Tuesday that the triggering of Article 50 must be undertaken by Parliament, not just the Conservative Brexit Government. The Prime Minister has already conceded the principle by saying that Parliament will vote on the deal when she eventually concludes it. Yet Yvette Cooper, the former Labour leadership contender, thinks that any MP voting against the triggering of Article 50 is on a par with Donald Trump.

Bluntly, I see no point fighting to protect the rights of Parliament against a controlling, extreme executive if MPs then throw away the power to protect those who need and expect their protection.

This is just too important a moment for progressives – liberals and social democrats – not to be united. For Yvette Cooper to compare people like her colleague Clive Lewis, Ken Clarke or even myself to Donald Trump is not only offensive, but it also it misses the point. Worker rights, freedom of movement, an international world order – all are under threat from Brexit. And, as it happens, from Donald Trump. In this great battle for our future, history will ask of progressives this: which side were you on? By attacking MPs who want to stop a hard Brexit that was never on the ballot paper MPs such as Cooper are lining up with Liam Fox, Boris Johnson and David Davis. Do they really want that to be their legacy?

I am saddened and bemused by Labour’s attitude to Brexit. Shadow Brexit Secretary Sir Keir Starmer in the Commons seemed to actually congratulate the Government for resisting a hard Brexit. This is beyond parody. Then Jeremy Corbyn threatened to order MPs to vote for the triggering of Article 50, before U-turning.

Liberal Democrats have been providing the real opposition to the Tories on Brexit, but we need other MPs to get on the right side of the argument.

We who campaigned for Remain must respect the result of the referendum. However, I don't remember anyone saying, as Theresa May now does, that we would leave the single market and the customs union without a deal in place to allow British businesses to export to the EU. Nor do I remember anyone saying that if we left the EU it would be to become a low-tax, low-regulation, small-government off-shore island of the sort Chancellor Phillip Hammond is now advocating. I do, however, remember a bus with a promise painted on its side of an extra £350m per week for the NHS if we voted Leave.

Yes, I respect the result of the referendum, but that should not mean letting the Tories lead us all in a race to the bottom. Will Leave voters’ faith in politics really be restored by tax cuts for international plutocrats combined with NHS and school cuts for British citizens? Will the estimated 90 per cent who favour staying in the single market (according to a recent poll) really feel their views have been respected if we pull out of the world’s largest market? The Leave vote was the result of promises from Johnston, Daniel Hannan and others that we would still be part of the single market. Now the Conservatives admit they will not respect those assurances about trade, or the extra money for public services.

It is clear the Conservatives are not only using the referendum to ditch Europe but also to ditch our entire post-war political consensus of a mixed economy and decent public services for all. It seems to me that they are the ones demonstrating disrespect towards the referendum.

The key for the Conservatives to force through their hard-Brexit, hard-right agenda is the parliamentary vote on Article 50. Are MPs such as Yvette Cooper really going to hold the door open for them to hurt the people who need and expect protection?

Cooper and I may be in different parties, but can’t we focus for once on something on which we can agree?