In 1997, Labour told us “Things Can Only Get Better”, before Tony Blair won a landslide general election victory.

This year, Rishi Sunak appears to have concluded that things are not going to get any better for the Tories if he delays an election until the autumn.

His dash to the polls on 4 July suggests that a prime minister with a reputation for caution and an obsession with spreadsheets is actually a gambler.

To call a general election with his party consistently trailing Labour by 20 points in the Sky News poll of polls at best looks courageous, at worst reckless.

If he can pull it off, however, he will have achieved the Tories’ greatest election win against the odds since John Major won a 21-seat majority in 1992.

Mr Sunak and Mr Major do have some things in common. Both were previously chancellor of the exchequer before becoming PM and both are accused by critics of being – well, frankly – a bit dull.

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But in opting for a summer rather than autumn election, the normally cautious Mr Sunak is gambling on a number of fronts: chiefly the economy, migration and his “stop the boats” Rwanda policy.

On the economy, at Prime Minister’s Questions a few hours before Mr Sunak’s shock announcement, he told MPs inflation was “back to normal” and “the plan is working”.

Well, up to a point. Yes, inflation has hit its lowest level in nearly three years. But the fall from 3.2% to 2.3% was not as big as the government had hoped for.

And a June cut in interest rates now looks less likely. And what has happened to Mr Sunak’s pledge to cut income tax from 20p to 19p in the pound by the general election? Gone, presumably.

After his Budget in March, an upbeat Jeremy Hunt, the chancellor, told Sky News his 2p cut in national insurance was “absolutely” not the “last throw of the dice” before the election.

With an October or November general election, which Mr Hunt clearly favoured, looking likely, another mini-Budget in September – with that promised income tax cut – was predicted.

But by opting for 4 July, the best the Conservatives can promise now in Mr Sunak’s dash to the polls is tax cuts after the election if he’s back in Downing Street. But we’ve heard all that before.

And on migration, the news is mixed. Nearly 10,000 migrants have crossed the Channel in small boats already this year – a record – and the numbers invariably rise in the better summer weather.

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So far, the threat of deportation to Rwanda hasn’t proved to be the deterrent the government hoped – but that could change once flights get off the ground next month. That could be a turning point.

Other good news for Mr Sunak in a snap poll is that although Labour are ready for an election, Reform UK are nowhere near ready. That was clearly a factor in the PM opting for an early poll.

The last general election held in July was in 1945, on 5 July, when Labour’s Clement Attlee – who had been deputy PM during the wartime coalition – defeated Winston Churchill with a 147-seat majority.

Margaret Thatcher was a fan of June elections, opting for 9 June in 1983, when she won a 144-seat majority, and 11 June in 1987, when her majority was 102 over Neil Kinnock’s Labour.

As for July, is a general election in high summer a good idea? Scots will complain that 4 July falls during their school holidays, which begin on 28 June and last until 16 August.

And what about the sporting calendar? The big sporting event of this summer is the Euros, in which Gareth Southgate’s England football team are strong contenders. 4 July is also in the first week of Wimbledon.

The Euros start on 14 June and if England – or Scotland, to be fair, but less likely – progress to the last 16, those games are between 29 June and 2 July and the quarter-finals on 5 and 6 July.

General election coverage competing with football mania? Is Mr Sunak hoping for less election coverage? Or are the Conservatives’ election hopes in the hands of Gareth and the lads?

If history is any guide, footie fan Mr Sunak will hope Harry Kane and the boys powering their way towards the Euros final will create a feelgood factor that helps him win at the polls.

According to political folklore, Harold Wilson blamed England’s World Cup quarter-final defeat by West Germany, four days before the 1970 general election, for his defeat by Edward Heath.

So while Mr Sunak apparently doesn’t believe things can only get better for the Tories between July and the autumn, he will be hoping England’s footballers help things get better for him by 4 July.