Despite another defeat in Saturday’s parliamentary sitting, Boris Johnson may yet have the last laugh. While all eyes are on the Brexit-related legislation, and there is much to get through parliament, there is still the Queen’s speech, which last week laid out the government’s legislative agenda. A vote on that agenda is expected in the coming week – and without a majority of MPs, Johnson could lose again. In the past, such a defeat has tended to result in the prime minister resigning, but with Johnson and his chief adviser Dominic Cummings in No 10 precedent and convention are out of the window.

What Letwin has achieved with his amendment will only hold off no deal or the hardest of Brexits in the short term

The opposition could call for a no-confidence vote after a Queen’s speech defeat, but Johnson could himself take the initiative by calling a general election before 24 October – by setting down an amendment to the fixed-term act which would require a simple majority. Johnson and Cummings know only too well that a Tory majority is theirs for the taking, as the current polls stand.

With Cummings in No 10, bullying and propaganda are also what it is about. One such tactic appears to be to encourage the EU not to grant the UK an extension, or make it appear they won’t; but what matters always is the law. A legal opinion I was involved in commissioning earlier this year, written by Kieron Beal QC and three other senior lawyers, states that the EU has a legal duty to all its member states to ensure that any withdrawal is not damaging to what article 13(1) of the treaty on European Union calls the “consistency, effectiveness and continuity of its policies and actions”. Article 13(2) spells out: “Pursuant to the principle of sincere cooperation the EU and the member states shall, in full mutual respect, assist each other in carrying out the tasks which flow from the treaties.” And until we leave, we are still a member state. With my lawyers – public-spirited citizens who are willing to work pro-bono for the good of our country – I am watching closely what Johnson is doing and, rest assured, this government will not be allowed to ride roughshod over our laws and our constitution.

It says a lot, meanwhile, about what is wrong with our electoral system that if Johnson were to win a general election convincingly, he would have a clear path to enact policies that the British public is increasingly resiling from. The hundreds of thousands who gathered in central London on Saturday to demand their say on any deal clearly now represent the majority of voters. According to Kantar, just 20% would back the new deal for Brexit.

‘The hundreds of thousands who gathered in central London on Saturday to demand their say on any deal clearly now represent the majority of voters.’ Photograph: Dylan Martinez/Reuters

Still, looking at the voting records of our MPs, and the political ideology of the cabinet, what Oliver Letwin has achieved with his amendment passed on Saturday will only hold off no deal or the hardest of Brexits in the short term. The fallout for the overwhelming majority of citizens who are struggling to make ends meet, or have taken for granted basic rights and protections, or have been welcomed in a tolerant, multicultural UK, will undoubtedly be very bleak.

This is not, however, a time to give up, but to be ready to vote tactically and to use our imperfect electoral system every bit as cunningly as Johnson and Cummings. My team and I at Remain United stand ready, in collaboration with the experts at Electoral Calculus, to launch a politically unbiased tactical voting website again, as we did for the European elections this year and in the 2017 general election. Back then, polls predicted Theresa May would gain an 80-plus majority, yet due in a large part to tactical voting she was only able to form a minority government – the consequences of which we are still seeing today.

In the election, a repeat of this strategy will involve a lot of people voting – in Polly Toynbee’s phrase – with clothes pegs on their noses as, quite frankly, voting blindly along the old party political lines would be a disaster for our country.

If we do still leave the EU with Johnson’s substandard version of May’s deal – or with no deal, and I still don’t rule it out, even after Saturday’s vote – reality will soon hit home and I believe vast swathes of Johnson’s supporters will turn against him. The damage will, of course, have been done – but what is clear to me is that whoever wins the next election, or whatever parties form a coalition, the government is unlikely to be in power for long.

A lot of far-sighted politicians on all sides of the house are now looking ahead to the general election after this one. Will all the present leaders then still be in place? I would not bet on it. I look to that future government to start to begin the long process of fixing what David Cameron – in such happier times – called Broken Britain.

• Gina Miller is a businesswoman and transparency activist who took legal action to prevent Boris Johnson proroguing parliament