Rishi Sunak and Sir Keir Starmer will dominate the headlines for the next six weeks, with one of the pair heading for Downing Street on 5 July.
But while the battle between the Conservatives and Labour will take precedence, the success of the Liberal Democrats and Reform UK will shape much of the outcome.
On the prime minister’s right he faces an onslaught from Reform leader Richard Tice, who took the reins of the former Brexit Party from Nigel Farage.
And on Mr Sunak’s left, attempting to win over more moderate disgruntled Tories, is the Lib Dems’ Sir Ed Davey.
Both parties are threatening to add to the scale of defeat facing the Conservatives, currently trailing Labour by 21 points in the polls.
But how many seats might the Lib Dems end up winning, and can Reform UK pick up any?
Reform UK election targets
Reform’s aim in the election seems to be to inflict as much damage on the Conservatives as possible.
Mr Tice has said the party will win seats, plural, but refused to say how many. And after a series of underwhelming by-election contests, pollsters don’t expect the party to win any.
The multimillionaire former Tory donor sounds much more believable when he talks about wanting to punish the Conservatives for having “broken Britain”.
“They need to be replaced,” he said at Reform’s campaign launch.
Mr Tice himself is standing in the country’s biggest Brexit voting constituency Boston and Skegness, where 75.6 per cent of voters backed leaving the EU.
And Reform’s only MP, Lee Anderson, is hoping to hold Ashfield, which he won as a Conservative in 2019.
Political analysts at Electoral Calculus forecast Reform will win zero seats, but in a best case scenario said they could win as many as 15.
Either way, it can inflict huge damage on the Tories by splitting the right-wing vote. Pollsters have consistently warned it could cost the Conservatives majorities in more than 30 seats as voters disgruntled with record taxes and migration rebel against Mr Sunak’s party.
Lib Dems hope to gain seats
By contrast, the Liberal Democrats are expected to win dozens of new seats and are taking aim at high profile Conservatives including several serving ministers.
Sir Ed has promised to smash the so-called blue wall of safe Conservative seats and launched his campaign in justice secretary Alex Chalk’s Cheltenham constituency.
His party is also presenting a real challenge to Jeremy Hunt in Godalming and Ash in what could be a stunning upset for the chancellor.
Electoral Calculus predicts the Lib Dems will jump from winning 11 seats in 2019 to 44 on 4 July. In the best case scenario, it forecasts Sir Ed winning as many as 58 seats, more than Sir Nick Clegg won in 2010 at the height of his popularity.
Recent by-elections have seen Labour and Lib Dem voters tactically choose the best candidate to oust Tory MPs, a trend likely to play out across the country in the general election as anti-Conservative sentiment runs rife after 14 years in power.
Other parties
Other parties whose performances will be crucial include the SNP, who are currently in meltdown north of the border and risk losing tens of MPs.
Senior party figures expect to lose at least a quarter of the party’s 43 Westminster seats, however polls point to a much worse showing.
A decade on from Labour’s wipeout in Scotland, it is enjoying a resurgence that could leave the SNP with just 12 seats.
The Green Party is also expected to pick up another seat, leaving it with MPs in Brighton and Bristol to challenge Labour from the left.
Jeremy Corbyn is set to announce his candidacy as an independent, with friends of the former Labour leader confident he would have the support to beat the party which has turned its back on him under Sir Keir.
But overall the polls as they stand point to a thumping Labour landslide. Electoral Calculus puts the probability of a Labour majority at 98 per cent, just four years after Mr Corbyn led it to its worst election defeat since 1935.
