It looks like our government is finally facing “make your mind up time”. Having spent so long living by meaningless slogans – “Brexit means Brexit”, “Deep and Special Partnership”, “No Deal is better than a Bad Deal” – the Conservative Party is now facing a choice between three bad options.

These are: trying to bluff our way into forcing the EU to capitulate to our wishes, risking an ideologically-driven hard Brexit if the EU cannot agree to our demands, or abandoning our commitments to Northern Ireland and reneging on international agreements that ensure the integrity of the United Kingdom. At least, these are the consequences of the Brexit red lines set out by the government.

It is hard to believe that the Tory Party – which is registered in Northern Ireland as the “Conservative and Unionist Party” – has adopted policies that put the unity of the UK in jeopardy. I do not envy the Prime Minister’s position, but she cannot continue for much longer with double-speak.

In December, she agreed that, if no other solution is found (and almost everyone knows there is no other solution available) there will be regulatory alignment between Northern Ireland and Ireland, to protect the Good Friday Agreement. This is a commitment that the EU and Ireland accepted in good faith. But soon afterwards, some ministers suggested that the agreement was meaningless and had been misunderstood. The EU now requires the wording which our government agreed in December to be put into a legally binding agreement. There seems to be some worrying backsliding going on. Our 27 partners cannot accept this.

The government’s “red lines” set us on course to leave the EU single market and customs union. The logical consequence of this is there must be a hard border between Northern Ireland and Ireland, or at the very least between Northern Ireland and the rest of the UK. There is no other real world solution. Unfortunately for the Prime Minister, it is not the EU that is trying to break up the UK – it is her own side.

These “Brexiac” (Brexit at Any Cost) red lines, which should never have been accepted, are an existential threat to the UK. Theresa May knows this. Yet, for the sake of the Tory Party, rather than our country, the PM has allowed her ministers free rein. The Good Friday Agreement, which is approaching its 20th anniversary, has succeeded in allowing us to move on from the days of sectarian violence and threats to mainland Britain, as well as peace and prosperity to the island of Ireland. Yet some Brexiteers go as far as questioning the Northern Ireland border agreements.

The government’s position seems indefensible. If we leave the customs union and single market, there must be a hard border in Northern Ireland. And if we tear up the Good Friday Agreement, the unity of the UK is at risk. It’s time to choose: we cannot have two mutually incompatible aims. We are also calling into question our trustworthiness as a nation that honours its commitments.

Many Conservatives are horrified at what is happening in our name. A few extremist Tories have hijacked the Brexit process and are being allowed to run riot, while our international standing is being undermined. Enough is enough.

I hope that on Friday PM May will say that protecting the Good Friday Agreement and the integrity of the United Kingdom is the reddest of her red lines. If other red lines have to be sacrificed for this, then so be it. If her hard Brexiteer colleagues are not comfortable, then I’m afraid she will have to face them with the facts.

All the huffing and puffing about deep and special partnerships or finding technological solutions cannot square this circle. I have tried to work out what the thinking could be that is driving the current situation.

Perhaps the game is to try to string things out until the last moment. I think some of the hardliners really believe that the EU will capitulate to our impossible demands because not to do so would be hugely damaging to them. Well, then we must ask what happens if this bluffing fails? If the EU cannot give us what these ideologues want, then we crash out with No Deal. That is not what they think will happen but what if they are wrong?

A minority of extreme Brexiteers apparently believe a No Deal Brexit is fine. They do not seem to care about Northern Ireland’s citizens or the UK’s national and international obligations. This ideologically driven position takes no account of the risk to jobs, business, our leading global position in many areas and just wants out.

A No Deal Brexit would leave us free of the EU, but shackled to a sinking ship, risking the break-up of our United Kingdom and losing all the free trade deals we have built up over the years, not just with our 27 nearest neighbours but also 60 or so other countries (including most of the Commonwealth plus Japan, Canada and South Korea) with whom we have trade agreements via the EU.

For a Conservative and Unionist Party that believes in free trade and private enterprise, while also caring about social values, taking such risks with our children’s future is reckless in the extreme. It’s time for the PM to lead our wonderful country away from the cliff-edge, rather than edging ever closer to it.

Baroness Ros Altmann CBE is a leading supporter of Open Britain.