The most striking moment in politics last week was not David Davis’s fifth (unfulfilled) threat to resign. Nor was it Boris Johnson’s latest (unpunished) violation of collective responsibility. It wasn’t even the spectacle of hours of intense cabinet psychodrama finally resulting in a customs proposal that was instantly shot down by the EU’s chief negotiator. In Brexitland, a lot happens – but very little changes.

No, the week’s most interesting political event came late on Monday, when the Speaker, John Bercow, asked if he had “the leave of the House” to grant Labour backbencher Stella Creasy an emergency debate on Northern Irish abortion law. In silence, the vast majority of the MPs present in the Commons stood up – and the debate was granted. Supporters of the motion included the new minister for women, Penny Mordaunt, and Karen Bradley, the secretary of state for Northern Ireland.

The gesture was strangely moving, and getting to that point had required some good old-fashioned parliamentary strategy. The support of 40 MPs is needed for an emergency debate, and Monday was a low-key, one-line-whip day in the Commons. Yet both Labour and Tory MPs slipped into the chamber, ready at just the right time, thanks to an effective and unseen marshalling operation. (Labour’s Margaret Hodge and Tory Andrew Mitchell achieved a similarly impressive feat when they stealthily secured cross-party support for greater transparency in tax havens last month, forcing the government to accept their amendment.)

The content of the next day’s debate was equally heartening for believers in parliamentary democracy. The Conservative MP Heidi Allen spoke about her own experience of needing an abortion when she was seriously ill with daily seizures. The DUP’s Sammy Wilson tried to argue that the current Northern Irish regime – which forbids terminations even for rape victims – was “balanced” between women and “the rights of the unborn child”.

He was promptly interrupted by Anna Soubry, who appears to have last given a shit some time in mid-2016. Standing resolutely with her arms crossed, she had a straightforward question: “So what’s he going to do about it? Are you going to get the 724 women [a year] who came to this country, to have abortions… to stay in Northern Ireland to have children that they don’t want?” (Wilson fell back on saying that it was a devolved issue.)

Play Video 1:55 MP Heidi Allen talks about her abortion in powerful Commons speech – video

The debate showed the Commons at its best – courteous, attentive to details, and largely free from partisan point-scoring. It clarified the issue at stake and scrutinised the proposed response. Revisiting Northern Ireland’s archaic restrictions on abortion – and its ban on same-sex marriage – is long overdue. When the Republic of Ireland voted resoundingly to liberalise its own laws on 26 May, it shamed British politicians into considering the experiences of women north of the border. The 1967 Abortion Act was never enacted there, and so the relevant legislation remains the 1861 Offences Against the Person Act. This declares that a woman can “be kept in penal servitude for life” for inducing a miscarriage. As Stella Creasy has pointed out, a rape victim who has an abortion faces a longer jail term than her rapist.

As in the Republic, Northern Irish women already have abortions. They travel to England – where, thanks to an earlier campaign by Creasy, their treatment is now funded by the NHS – or buy pills off the internet and risk being arrested. I met three campaigners who had deliberately bought such pills and then handed themselves into police as a protest. It was notable that they were all retired. Why? Because, as they pointed out, a conviction under the 1861 Act counts as assault, and would show up on criminal records checks and visa applications to America or Australia. (Two years on, they are still waiting to hear if they will be prosecuted.)

That is the cruel reality of the current laws. A 2016 poll by Amnesty suggested that 70% of Northern Irish voters back reform. The stumbling block is the DUP, whose leaders remain hardline social conservatives, even as their constituents have become more liberal. It is extremely convenient for Arlene Foster, Nigel Dodds and the rest to point to the collapse of the Northern Ireland assembly as an excuse for keeping the status quo.

Other “pro-life” commentators and MPs have tried to derail the discussion by suggesting a referendum. But this is not needed: while the Republic’s written constitution can only be amended by a popular vote, there is no such barrier to changing the law in Northern Ireland. A referendum would only cause division and delay.

That brings us to Creasy’s strategic insight. Instead of trying to extend the 1967 Abortion Act to Northern Ireland – and face down the resulting howls about devolution – she is proposing something more simple and more radical. The 1967 Act works by providing exemptions to the 1861 Act – allowing abortions in certain circumstances. So why not just repeal the relevant clauses of the older legislation? That would decriminalise abortion up to 24 weeks(after which point the 1929 Infant Life Preservation Act kicks in) and allow the constituent nations of the UK to introduce their own new frameworks.

Changing the “ask” to repealing Westminster legislation rather than over-riding a devolved assembly has made the proposal palatable to Scottish nationalist MPs such as Hannah Bardell and Alison Thewliss. It has also won over Sinn Féin’s leader, Michelle O’Neill, who said Northern Ireland risked becoming “a political, cultural, backwater, to keep the Tories in power”.

Facebook Twitter Pinterest Sammy Wilson, DUP MP for East Antrim, opposed any changes to the Northern Irish law. Photograph: Liam McBurney/PA

Real progress now seems possible – which is quietly astonishing in itself. For decades, the feminist consensus has been that revisiting our abortion law is too dangerous to contemplate in case the well-funded and increasingly well-organised “pro-life” movement successfully lobbies MPs to cut the upper time limit or impose new restrictions. (Several leading Tories, such as the health secretary, Jeremy Hunt, personally support lower limits.)

The impression that the current situation is unjust and untenable was bolstered by the supreme court’s ruling that Northern Irish law violates human rights – even if the petition itself was rejected because it was brought by an organisation rather than an individual. We might now see a similar case brought by a single rape victim, which would deeply embarrass the government.

Meanwhile in parliament, the spotlight will now shift to the newish home secretary, Sajid Javid, who has so far remained completely silent on the subject. (And most other subjects, to be fair.) Repealing the 1861 law could be achieved through an amendment to the domestic abuse bill, one of the few pieces of non-EU legislation on the parliamentary agenda. It is promised within the current session, but that is scheduled to run into next year. Javid is under pressure to speed up its arrival.

One last point. The lack of histrionics involved in advancing abortion reform does not mean that the fight has been easy. Creasy – already squaring off with Momentum activists in her Walthamstow constituency who want to deselect her – has received little support from her party’s leadership. Karen Lee, the shadow minister for fire, criticised Creasy, saying that the motion should have been run by the frontbench. The shadow attorney-general, Shami Chakrabarti, had earlier spooked some wavering Tories by declaring that reform was a test of Theresa May’s feminism, which threatened to turn a non-partisan issue into a test of their loyalty to the prime minister. The spirit of collaboration has its limits.

Still, it is notable that all of this has happened without any of the headline-generating bombast of David Davis and Boris Johnson’s antics over Brexit. From Dr Sarah Wollaston to Thewliss to Caroline Lucas to Jess Phillips, the roll call of MPs involved reads like an alternative House of Commons, where pragmatism and cooperation count for more than ego-driven bluster and knowing three dozen words of Latin. (It is tempting to reduce this to a point about gender – oh, if only women ran the world! – but several men also spoke eloquently in the emergency debate.)

A poll last week revealed that even 71% of Leave voters think Brexit is going badly. They are, to put it mildly, not wrong. The pointless melodrama, unforgivable lack of preparation and selfish short-sightedness that swirls around our exit from the EU is enough to make you lose faith our politicians. Until, that is, you remember the sight of MPs quietly getting to their feet, and working together for a cause they believe in. Because that is politics, rather than posturing.

• Helen Lewis is deputy editor of the New Statesman