Theresa May thought her Brexit deal was an offer MPs could not refuse. Not because it would bring our constituents anything useful. Quite the opposite – it will make us poorer, our economy less certain and our outlook less hopeful. Take the prime minister’s Brexit deal or crash out of Europe with no deal at all, she declared.

But far from being the Don Corleone of British politics Theresa May is more the emperor with no clothes. Explicitly keeping the option of a no-deal on the table is an act of supreme economic sabotage. It is also delusional. The prime minister has long preferred the support of hard right Brexiteers over more reasonable voices within her party. Now she is seeking the votes she needs by threatening these same Brexiteers with something they actually want – a no-deal Brexit. Her attempt at blackmail is both stupid and venal.

Some Tory MPs want a no-deal Brexit because they have rightwing dreams of imperial revival or libertarian utopia – let’s say hello to the monocultural European Research Group. Others simply want May to fail spectacularly so they can claim they would have done better – the famously principled former mayor of London comes to mind. They are not going to be responsive to Theresa May’s threats because for them no deal is better than her bad deal.

Despite the pomposity, the pantomime theatrics and the last-minute cop-out, it may be that the prime minister thinks she is doing the responsible thing – I can only hope she watched Rebel Without a Cause over the Christmas break. She is setting us up to be the car whose driver gets his sleeve caught in the door in a drag-racing game of chicken and goes over the cliff.

But it is hard to have faith in May’s motives when she has chosen to deliberately run down the clock, causing further cost and chaos. She hopes MPs will quietly vote for her deal, blinded by the oncoming “no-deal” headlights. But in reality her deal won’t withstand the internal contradictions of the Conservative party which cannot support a permanent customs union even though it is essential for our economy.

May hopes MPs will quietly vote for her deal, blinded by the oncoming 'no-deal' headlights

My constituency is in the north east, the only region to export more than it imports. Half of that is to the EU. Companies big and small have sales and supplier links that cross the Channel not once but many times. Throughout the UK, businesses, many with traditional Tory allegiances, are waking up to the fact that their EU connections are not based on one company or one product or one service or one person, but are numerous and interdependent. This web of economic activity cannot be undone in a matter of weeks or even months, and it certainly cannot be replaced by dubious future trade deals with America, Africa, Australia or other distant lands. Our economy demands more.

So in reality Theresa May has two responsible choices. She can call an election and give Labour a chance to actually do what she is manifestly incapable of doing, and that is govern. Or she can pursue a deal that actually is in the interests of our country, a customs union that preserves workers’ rights and environmental protections, and ensures there is no hard border on the island of Ireland.

But at this late date, after she has wasted two years in a dance of death with extreme Brexiteers, we must recognise the challenge of negotiating a deal that obtains cross-party support before the March deadline. Labour’s conference motion does not reference an article 50 extension but we have acknowledged it may be necessary. More recently Frances O’Grady, general secretary of the Trades Union Congress which includes representatives of all sides of Brexit, called on the government to suspend article 50. Increasingly it is clear that the options to avoid an economic and social catastrophe are general election, public vote and/or article 50 suspension. With each day that passes Theresa May’s inept blackmail makes it harder to do anything responsible without stopping the clock.

• Chi Onwurah is the Labour MP for Newcastle Central, and is shadow minister for industrial strategy, science and innovation