LONDON (Reuters) - The Scottish National Party was set for its worst showing at a British parliamentary election since 2010, an exit poll said on Thursday, projecting it would win just 10 seats amid a predicted resurgence for the Labour Party in its traditional heartlands.

The SNP, which held 43 seats before the election was called, has suffered from a period of turmoil that has seen two leaders quit in little over a year, a police investigation into the party's finances and splits on a range of policies including its attempts to secure a second referendum on independence.

Former leader Nicola Sturgeon said the exit poll was at the "grimmer end of expectations" for her party, but said she expected it would be proved broadly correct.

The SNP has dominated the British parliament's Scottish seats since 2015, garnering the support of pro-independence voters in the wake of a 2014 referendum where Scots voted to remain part of the United Kingdom by 55% to 45%.

While the 2014 referendum failed to deliver independence, it did unite many supporters of the cause behind the SNP, which won so dominantly in 2015, 2017 and 2019 that it was the third largest party in the Westminster parliament despite contesting fewer than 10% of possible seats.

Overall Labour were projected in the exit poll to win 410 of the British parliament's 650 seats, giving it a landslide majority, though there was no immediate figure for how many of Scotland's 57 seats it was set to gain. It won just one seat in Scotland in 2019.

If the exit poll results were borne out, the Liberal Democrats and the right-wing Reform party would overtake the SNP in the number of seats they held in the Westminster parliament.

(Reporting by Alistair Smout; Editing by Alex Richardson)

By Alistair Smout