Will the Tories’ election gamble pay off? Or will Boris Johnson follow in the footsteps of his predecessor and regret his decision to call a snap poll? Win or lose, the Boris’s fortunes are likely to be decided in a handful of marginal seats up and down the country. If the Conservatives can win back Brexit party voters – and also stave off a challenge from the Lib Dems – then PM Boris could enjoy the kind of healthy majority which eluded Theresa May. But if he loses, Britain could wake up to Jeremy Corbyn in Number 10 on 13 December. These are the seats which will determine who wins:

1: North East Fife

If one voter had stayed at home at the June 2017 snap election, North East Fife could have had a different MP. The SNP constituency is the most marginal seat in the UK, with a majority of just two. The SNP first won the seat back in 2015 but before then it had a Lib Dem MP. Jo Swinson will be looking to win back North East Fife and it is likely that the party’s ‘bollocks to Brexit’ strapline could be a hit in a city that voted 59 per cent remain in the EU referendum.

2: Perth and North Perthshire

The second most marginal constituency is also north of the border, with voters in Perth and North Perthshire electing their SNP MP Pete Wishart by a majority of just 21. It was Ian Duncan, the Tory candidate, who came second in 2017. And this is just the sort of seat Boris Johnson’s party must pick up if it is to secure a healthy majority in a new parliament. Last year, Wishart warned that the SNP might alienate Brexit voters if it continued to ‘chastise’ them. The Tories will be hoping that he was right and that the damage has been done.

3: Kensington

Kensington will probably be one of the most fiercely contested seats at the snap election, as Corbyn comrade Emma Dent Coad attempts to defend her majority of just 20 votes. Labour’s victory in 2017 was their first win in the seat and the party’s success in west London summed up a dismal night for the Tories. Yet the Conservatives, who have a new candidate in Felicity Buchan, will be optimistic about ousting Dent Coad. If so, they face two major obstacles. Public anger over the Grenfell Tower tragedy in which 72 people lost their lives, was partly directed at the local Tory-held council. Dent Coad herself accused Kensington and Chelsea Council of either ‘racism or snobbery’ following the deadly blaze. The Tories also face a challenge from a former MP of theirs, Sam Gyimah, who is standing as a Lib Dem candidate in the seat; the Leave vote in Kensington and Chelsea in 2016 was just 31 per cent.

4: Dudley North

Another Labour seat the Tories will be hoping to win, Dudley North was one of the few seats that saw the Conservatives up their share of the vote in 2017. Ian Austin has a majority of just 22 – down from 4,181 in 2015. Dudley resoundingly backed Leave at the EU referendum by 68 per cent to 32 per cent. So unless the Brexit party succeeds in splitting the Leave vote, it seems likely that Austin could be a casualty of Labour’s muddled Brexit message.

5: Southampton Itchen

Southampton Itchen has traditionally been something of a battleground between Labour and the Tories and this year will be the same. The Tories will be hoping to increase their wafer-thin 31-vote majority from 2017 back to the level it was in 2015 (2,000+). But Simon Letts, the Labour candidate who narrowly lost out last time, will be hoping to reverse the Tory victory. If he does, it will be in keeping with a seat that has returned a Labour MP 14 times to a Tory member on just four occasions. But if the Tories do lose out here it will spell bad news for Boris Johnson and suggest that his election gamble has backfired.

6: Newcastle-under-Lyme

Labour has won Newcastle-under-Lyme at each of the last six general elections by a smaller majority than the previous occasion. In 2017, only 30 votes separated Labour’s Paul Farrelly and the Tories’ Owen Meredith. Two years ago, Farrelly was one of only 13 MPs to vote against triggering a snap poll. He has done the same this time around. Given that Newcastle-under-Lyme is high up on the Tory target list, it’s no surprise that he is once again nervous about his prospects.

7: Richmond Park

Richmond Park is likely to be top of the Lib Dems’ target list at the election. The party’s MP Sarah Olney was ousted in 2017 by Tory candidate Zac Goldsmith. Fewer than 50 votes separated the two parties then. Given that Richmond had a Remain vote of nearly 70 per cent, it is likely that the Lib Dems’ anti-Brexit pitch will be a hit on the doorsteps of west London.

8: Crewe and Nantwich

Tory candidate Edward Timpson won three elections on the trot in Crewe and Nantwich, only to lose his seat by just 48 votes in 2017. The Conservatives have a new candidate this time: Kieran Mullan, who will be hoping to reverse the party’s defeat and oust Labour MP Laura Smith.

9: Glasgow South West

The SNP held on to their Glasgow South West seat in 2017 – but only just, as their healthy majority of 10,000 was slashed down to just 60. In December, it is likely to be a less closely-run affair, with the SNP currently polling on 39 per cent in Scotland – and Labour trailing them by 20 points on 19 per cent.

10: Glasgow East

It’s a similar story across the city, where the SNP’s David Linden will be attempting to stave off Labour’s challenge and defend his 75-vote majority. Expect the SNP to hold this seat by a majority similar to the 10,000 vote one they had in 2015.