Today’s Sunday Times splash – about a ‘coup’ being plotted by Tory rebels to take over Brexit – looks and feels like it was dreamed up in No. 10. It wasn’t and the story shouldn’t be dismissed because of that. The Speaker’s actions last week have changed the calculations: something previously judged procedurally impossible (for rebels to call the shots in parliament) is now a genuine risk. In my view, it risks the very stability of the government.

The story so far: that Dominic Grieve and Oliver Letwin are seeking a way to seize control of business in the Commons, so that backbench motions take precedence over government motions. This matters because, until last week, a whole load of options were unthinkable. Tory rebels may be frustrated but they could not act on their plans because they could not call them to a vote. Under the Westminster system the government controls the agenda parliamentary agenda. Or did, until John Bercow upended things last week.

Now we read that Nick Boles is seeking a way to introduce a bill which could override the EU Withdrawal Act and compel the government to seek an extension to Article 50, presumably by imposing a legal duty on ministers. We should assume the various Remain rebels are comparing notes and a combined amendment is likely to emerge.

Tactically, it’s risky for No. 10 to draw attention to all this. It might embolden the rebels, who could benefit from the publicity. But on the other hand, denouncing this as an attempted coup might highlight the risks for other Tories tempted to support Boles or Letwin next week.

Control of legislation is one of the few tools available to minority government – this allows you to pick your battles and when you will fight them. Without that, you are on the run. That’s why Bercow’s behaviour, which he accepts is contrary to the advice of the clerks, is potentially game-changing.

So what is Nick Boles up to? He has said he’ll publish his plans on Tuesday, which suggests he will seek a vote after the deal is rejected or amended. He could of course change his mind and table it tomorrow, knowing he would have further opportunities to bring it back.

If a hostile amendment passes and deprives the government of control of the parliamentary schedule, then everything changes. The government will in effect become the opposition, seeking desperately to prevent a bill that would revoke or extend the Brexit process. The Prime Minister will no longer command a majority.

In such a situation, where power has been seized, what can government do? The majority is gone. Yes, of course the whip can be removed from rebels, but to what effect? It will rapidly become clear who is in charge: Labour, supported by the other opposition parties, and a small group of rebel Conservative MPs.

All of this was unthinkable on Monday – I categorically judged it impossible. No longer. And if it happens, we will be much closer to a General Election.

Nikki da Costa is a former director of legislative affairs for Theresa May.