If the end is nigh for Rishi Sunak, should we worry that he will try too hard to leave a legacy?

As Theresa May leaves the stage, her political obituaries are a warning to Rishi Sunak. Like most prime ministers, she will be remembered for only one thing, in her case her failure to break the parliamentary deadlock over Brexit.

Identifying the “one thing” for which prime ministers are known is a game that traditionally starts with Stanley Baldwin, remembered for his slogan “Safety First”. Ramsay MacDonald betrayed the Labour Party. Neville Chamberlain is forever associated with appeasement. Winston Churchill won the war. Clement Attlee built the welfare state. Anthony Eden is remembered for Suez; Harold Macmillan for “never had it so good”; and Alec Douglas-Home for counting with matchsticks.

Harold Wilson had “the pound in your pocket”; Ted Heath had the three-day week. James Callaghan had the winter of discontent. Margaret Thatcher had the Falklands. John Major had “Black Wednesday”. Tony Blair had Iraq; Gordon Brown had the financial crash.

Three prime ministers will be remembered for Brexit: David Cameron for the referendum; May for failing to implement it; and Boris Johnson for taking Britain out of the EU.

Several of these single phrases are unfair. There is a strong argument, for instance, that Chamberlain bought time to allow Britain to rearm. In many cases there are rival claims to more important legacies. Heath led us into the Common Market that took three prime ministers to get us out of. Thatcher broke the unions. Blair negotiated the Good Friday Agreement and saved the public services. And Johnson might be just as much remembered for lockdown parties as for getting Brexit done.

But generally folk memory is selective and cruel, and prime ministers are allowed one thing. Liz Truss will be remembered as the shortest serving prime minister long after the facts of her mini-Budget are forgotten.

Which brings us to Sunak. What will he be remembered for? When I last played this game, I suggested he might find the word “Rwanda” carved on his figurative gravestone. But it seems unlikely that history will remember a policy that never actually succeeded in flying a single person to the intended destination, no matter how shocking the waste of public money spent on it might seem.

It now seems certain, incidentally, that no plane will take off with asylum seekers on board before the election. If it is in November, there are just eight months left, and regardless of what happens in the House of Lords, that is no time at all in the courts. However much the legislation may be framed to try to avoid legal challenges, there will be legal challenges – and before we know it Sunak will be at the palace asking for a dissolution.

What else could it be? Cancelling HS2? Banning smoking (very slowly)? Something complicated to do with A-levels? I don’t think so. At this rate, Sunak is in danger of being remembered for something as unrelated to the content of his character as being the first Asian British prime minister.

He will be keen to avoid this fate, and therein lies the jeopardy for the rest of us. Desperate prime ministers thrashing around in search of a legacy are a danger to themselves and others. Blair handled his final lap of honour quite well, going on a farewell tour, giving big speeches and taking some difficult decisions on renewing Trident and pensions reform so that Brown wouldn’t have to.

But Theresa May left a more unexpected legacy, committing the nation to net zero carbon by 2050. It was a subject she hardly mentioned before or since, yet it will have momentous consequences in constraining her successors – already, less than five years on, the “pragmatic and proportionate” Sunak is trying to postpone some of the intermediate targets. The problem with net zero is that May seized on it as a big round number for her legacy’s sake without making the popular argument that will sustain it.

Sunak seems to be yielding to a similar desperation. He is trying too hard to bribe the voters in an attempt to stave off a humiliating defeat at the election. It may even work, up to a point. It is possible that the two big tax cuts this year, worth £950 to someone on average earnings, might start to have an effect over the next eight months. Especially if earnings continue to rise faster than prices, and if a further tax cut is promised in the pre-election fiscal event – in effect a second Budget – that is likely to kick off the five-week campaign.

But at what cost to Sunak’s historical reputation? I think the chances of him stopping Keir Starmer from becoming the next prime minister are remote. A hung parliament with an anti-Tory majority is the “reasonable worst-case scenario” for the Labour Party, to borrow the language of pandemic planning. So Sunak should ask himself if it is worth doing so much damage to the public finances of the next parliament just to save a handful of Tory seats.

Each tax cut delivered or promised before the election is bought at the expense of deep notional cuts in public spending after the election. Some Tory officials who call themselves “strategists” may be pleased to have laid such a “trap” for a Labour government, forcing it to put up taxes when it promised not to or to cut spending, which would be painful. But this pre-election bribery is simply irresponsible, and the more Sunak sells out his unique selling proposition as the guardian of prudent public finances, the less kindly history will look on him.

He wanted to be remembered as the chancellor, and then prime minister, who protected people with the furlough and the energy price subsidy, and who took the responsible decisions to keep the economy and the public finances on an even keel so that such protection could be afforded.

Yet now he is in danger of going down in history as the prime minister who left the books in such a state that his successors had to resort to emergency measures to prevent the collapse of public services.