There is still no united front on how to stop the UK crashing out of the EU on 31 October

At least 35 Conservative MPs have fired warning shots to Boris Johnson that they are strongly opposed to a no-deal Brexit. But there is no united front on what outcome they want instead and how far they are prepared to go to stop the UK crashing out of the EU on 31 October.

A tiny minority are seriously considering voting against Johnson in a confidence motion at the earliest opportunity, with Guto Bebb, a former minister, making the loudest noises about potentially working with the Labour leader, Jeremy Corbyn, and Philip Lee, another former minister, thinking about defecting to the Liberal Democrats.

But a much larger number are still reluctant to make a decisive move against Johnson, hoping that he will pivot towards a deal.

Many of this group are on holiday, giving approval for their signatures to be added to a letter of protest via Skype and WhatsApp.

“I’m in denial to be honest,” said one Conservative MP who is against a no-deal Brexit and is on a break with their family. “I have no idea what I’m going to do in September and even less in October.” Another said she was avoiding the news and trying to forget about politics until hard decisions had to be made when parliament returns.

Here are the major groups among the no-deal rebels – and what motivates them.

The parliamentary brains

Dominic Grieve and Oliver Letwin are the strategists trying to figure out a parliamentary mechanism to prevent a no-deal Brexit without resorting yet to collapsing the government in a confidence vote.

Grieve, a supporter of a second referendum, has been orchestrating these efforts from holiday in Brittany, France, and has indicated he could be willing to vote down Johnson’s administration if other parliamentary means do not work. These Conservatives are joined by a number of Labour thinkers, including Yvette Cooper and Chris Bryant.

The rebel foot soldiers

There are a close bunch of Conservative MPs, many of whom backed Theresa May’s Brexit deal, who are strongly opposed to no deal and are likely to vote against the government for any measure to stop it.

Some, such as Antoinette Sandbach and Jonathan Djanogly, have been rebelling for longer than others, and some, such as Alastair Burt and Sarah Newton, are former ministers who have only recently taken the plunge. However, this group are highly unlikely to back a no-confidence vote if it could lead to a Corbyn government.

The Gaukewards

Led by Philip Hammond, David Gauke and Rory Stewart, this group of former cabinet ministers will hold a fair degree of sway among centrist colleagues. If they support an option, then many others could swing behind them.

They are expected to join legislative efforts to prevent a no deal. It is a possibility that in extremis they could vote down a Johnson government, but they will exert all kinds of political pressure before that point. They are extremely unlikely to back any Corbyn-led temporary government.

The Tories on the edge

These are the most dangerous to Johnson. Bebb has said he is standing down as a Conservative so has little to lose within his own party and this week called Johnson “despicable”. He has said that a short-term Corbyn government is less damaging than the generational damage that would be caused by a no-deal Brexit.

Lee has said he is taking the summer to consider his future in the party. There are several more who say they could not stand again as Conservatives on a no-deal platform and therefore may have no future in Johnson’s party.

Grieve shows no inclination to defect from the party but has suggested he could vote against the government in a vote of no confidence if Johnson pursues no deal, as has the Tory grandee Ken Clarke. If this group swells, the prime minister is in serious trouble.

Those making a point

Some Conservatives have specific motivations. One Tory MP, Alberto Costa, signed the Hammond letter to demand that Johnson legislates to protect citizens’ rights if he is going to pursue a no-deal Brexit.

Others are now committed to a second referendum, including the former education secretary Justine Greening. One of the most interesting in this group is the former minister Sam Gyimah, who gave his name to the letter endorsing the need for a deal even though he voted against it three times and wants a second referendum in all circumstances.

These are an unpredictable bunch – and no one knows just how far they might go in pursuit of their preferred option.

The ministers

Amber Rudd and Matt Hancock do not want a no-deal Brexit. Boris Johnson assured them there was only a tiny chance of one to gain their support in the leadership election.

Nicky Morgan, who once joined efforts to ensure a parliamentary vote on the deal, is now in the cabinet and backed the Malthouse compromise for a managed no deal. Likewise, Jo Johnson, the prime minister’s brother, who had backed a second referendum, is back in the bosom of government. They are ultra loyal for now.

But if it comes to a Johnson government making no deal the official policy and committing to the UK crashing out on 31 October, then their interests may diverge from those of the prime minister. They are keeping their powder dry, but walkouts to oppose a no-deal Brexit cannot be ruled out in the months to come.