Space analogies are commonplace in 10 Downing Street these days. Boris Johnson has said proof the UK can leave the EU on 31 October could be found in the 1969 moon landing. In Dominic Cummings’s first meeting with government aides, he gave them a presentation on the lessons they could learn from John F Kennedy’s space programme.

Now there’s an official Apollo dashboard in operation – a traffic light-system signal available to more than 200 ministers, No 10 staff and aides. They are supposed to access it to track no-deal preparedness and flag when a project is in trouble and requires extra attention. The spreadsheet is also on the prime minister’s personal laptop.

On Tuesday, MPs are expected to force through a bill to make Johnson request an article 50 extension

The guiding idea is that achieving exceptional outcomes requires a shake-up, a reconfiguration and a new way of thinking. For landing on the moon, read landing Brexit.

To that end, what Cummings originally had in mind was a “radically different organisation” of the UK Brexit negotiating team. But just over a month in, the changes he has overseen go far beyond one group. As MPs return to parliament this week for a climactic Brexit showdown, the Conservative party is on the brink of lasting radical transformation and the pace is quickening at breakneck speed.

Johnson’s decision to prorogue parliament for five weeks means that the window for anti-no deal MPs to act has been fast-tracked to this week. Those wavering Tory MPs who had hoped to postpone their personal moment of truth to give him time to agree a Brexit deal no longer have that luxury. On Tuesday MPs are expected to take control of the order paper and force through a bill to make the prime minister request an article 50 extension.

In response, Johnson and his team plan to fight fire with fire. The Conservative leader today issued his MPs an ultimatum: back him or allow Jeremy Corbyn to take over and “plunge the country into chaos”. To hammer this point home even more assertively, dissenting Tory MPs could be threatened with deselection. No 10’s aim is to present them with a simple choice: Johnson or Corbyn, making clear that the wrong decision will be career-ending.

Downing Street remains bullish about being prepared for any turn of events. Johnson’s director of legislative affairs, Nikki da Costa, has told querying colleagues that they have been preparing for this for two years. Insiders say there is an acceptance that things will get very hairy, but stress that every possible scenario has been war-gamed. “While David Gauke has been taking photos on holiday with a unicorn inflatable, we have been working around the clock,” says a government source. And a former minister who currently sits in the Gaukeward squad of anti-no deal MPs complains that it is difficult to anticipate how Cummings – who has written extensive blogs on strategy – will play it.

However things play out this week, the dilemma for the anti-no deal Tories will remain much the same. The Conservative party under Johnson is set on a path that many cannot reconcile with their consciences. Even if MPs manage to legislate against a no-deal Brexit, Johnson will try to ignore it, and if need be aim for a general election on a manifesto to leave the EU – deal or no deal.

That idea is so toxic to some would-be rebels that talks are under way for a group of about 20 MPs to form a breakout party and stand as independent Conservatives. Other Tory MPs have lost the will to fight and are considering simply not seeking re-election.

‘In Cummings’s meetings, you’re as likely to hear a no-deal Tory sceptic criticised as you are a Labour politician.’ Photograph: James Veysey/Rex/Shutterstock

An ideological change is taking place across government and in the wider party. One former minister refers to it as “a Vote Leave takeover”. Many of those who worked on the leave campaign in the EU referendum now reside in Downing Street, but the growing Vote Leave influence extends well beyond.

Aides who have found to be insufficiently committed to no deal have been blocked from returning to government; some of those who have made the cut describe a culture of fear. In Cummings’s weekly meetings with aides, you’re as likely to hear a no-deal Tory sceptic like Dominic Grieve or Philip Hammond criticised as you are a Labour politician.

On the cabinet conference call to discuss prorogation, Amber Rudd raised concerns with Johnson about the aggressive tenor of the Brexit rhetoric coming from No 10. “It’s actually scary how quickly they have managed to take control of so much,” says a Tory source.

The consequences of the new mindset are far reaching. Cummings’s decision to sack Sajid Javid’s aide without the chancellor’s knowledge has led to reports of tensions between No 10 and No 11. While both Javid and Johnson have played down any problems in their relationship, certain figures in No 10 regard Javid as a victim of Treasury group-think. Among this group, his Treasury colleague Rishi Sunak – the chief secretary to the treasury – is viewed as the more on-message of the pair.

Expecting an imminent election, several cabinet ministers are keeping their heads down – worried that if Johnson returns with a majority and they have gone off piste they will be the next ones to be shown the door.

Johnson allies play down the idea of an election being called as early as Thursday. Even if legislation is passed, Johnson and his team will probably make a few more attempts at getting round it. Any extra time for Downing Street to push its key messages is seen as a good thing. The crunch could come next month when few believe this government will manage to pass a Queen’s speech as they have pledged to do in mid-October.

The transformation that is going on within the Conservative party is matched by a change in electoral strategy. The voters Johnson and Cummings are prioritising in any early election are different from those David Cameron aimed for in 2015. The focus is on those who voted leave in the EU referendum. The first priority is to reunite the leave vote from the referendum and kill off the Brexit party. The seats the Tories would target are areas that voted heavily to leave – many of which are Labour/Tory marginals. The Liberal Democrats are viewed as a bigger concern for Labour – eating into the pro-EU vote.

Already, Johnson is transforming the party he aspired to lead for so long. Retiring opponents of no deal are being replaced by devoted advocates of it – and even those who backed remain are seeking selection as “reformed remainers”. The Conservatives are changing. According to one party source, “The candidates in a snap election will be Vote Leave mini-Mes.”

The process could yet be thrown into reverse. The hope remains among some Johnson allies that an election will be held off until after the UK has left the EU. At that point, lots of the problems could go away. If there is no exit to argue about, there could be less intolerance towards anti-Brexit MPs and vice versa. “It would be more of a pacifying position,” says a government insider.

However, for many of the no-deal rebels, the party is shifting so far from the one they joined that they would struggle to lay this to rest in the event of a no-deal Brexit.

The truth is that anti-no deal Tory MPs must now decide whether they can remain in a party that has shifted to be a party of leave. If the answer is no, this week is as good a time as any to find the door.

• Katy Balls is the Spectator’s deputy political editor