A 59-WORD plan to crack down on non-residents selling property in Britain was only a small move by the chancellor in the budget on November 22nd. But it marked a big victory for Stella Creasy. The backbench Labour MP had for weeks demanded that the government close a loophole through which foreign property-owners could avoid capital-gains tax when selling up. Now they will have to cough up £470m ($630m) over the next six years.

It capped off a legislative hat-trick for the MP for Walthamstow, who has a knack for turning campaigns into law. This summer Ms Creasy led a successful push to provide free abortions for women from Northern Ireland on the British mainland. In the previous parliament, she hounded the government into clamping down on payday lenders. All three cases demonstrate the impact a single MP can have, even when in opposition.

Yet enterprising politicians such as Ms Creasy are thin on the ground. Part of the problem is systemic. Whereas American congressmen make names for themselves by proposing bills on an individual basis, Britain’s system “does not encourage this sort of behaviour”, says Philip Cowley of Queen Mary University in London.

First, there are few avenues for backbenchers to turn pet projects into law. Private members’ bills, the main route available, are easily squished by filibustering. There have been high-profile successes: in the 1960s bans on abortion and homosexuality were lifted, and the death penalty abolished, thanks to private members’ bills. But these pieces of legislation succeeded thanks to a home secretary who was willing to give them time and support.

Second, MPs keen on advancing their own careers will usually avoid trampling on the toes of their party’s leadership by proposing their own amendments. British MPs are more dependent on their parties for promotion and funding than are their American counterparts. That makes them more obedient. MPs seeking a quiet life are content to spend their career as “lobby fodder”, wandering whichever way the whips in charge of corralling MPs tell them, adds Mr Cowley.

But now the balance is tipping in favour of backbenchers. Current parliamentary arithmetic gives them clout: only seven Tory MPs have to rebel before the Conservative government stares at defeat. Rebelling against your party can still hinder a career, but often the government will blink first and alter course rather than face a parliamentary rout. In any case, former rebels can still rise to the top. Jeremy Corbyn, who now leads the Labour Party, voted against it a sixth of the time when he was a backbencher and the party was in power. Partly for that reason, many of his own MPs do not much fear the Labour whip.

The ranks of the backbenchers have also been reinforced. Both Labour and the Tories have overhauled their cabinets in the past two years—the Tories after the Brexit vote, Labour following the rise of Mr Corbyn—casting experienced MPs to the backbenches. Hilary Benn, a former shadow foreign secretary sacked by Mr Corbyn last year, has hailed the current session as a “backbenchers’ parliament”.

Lastly, backbenchers have a bit more institutional power than they did. A Backbench Business Committee, set up in 2010, helps MPs organise votes on personal topics. Online petitions and social media enable them to create a stink. When coupled with an unstable government, the conditions are ripe for backbench MPs to take the initiative. Somebody has to.