Anas Sarwar has hailed a "seismic result" for Scottish Labour, after the party routed the SNP in the Rutherglen and Hamilton West by-election.

He said the result would "send shockwaves through the SNP." 

Michael Shanks was declared the new MP for the South Lanarkshire seat after beating the SNP’s Katy Loudon by 17,845 votes to 8,399.

The results give the new Labour MP a majority 9,446, and represents a 20.4% swing.

The Scottish Conservatives came in a distant third place, with Thomas Kerr polling just 1,192 ahead of Scottish Liberal Democrat candidate Gloria Adebo, and Scottish Green Party candidate Cameron Eadie who secured 895 and 601 votes respectively.

READ MORE: Labour crushes SNP in historic Rutherglen and Hamilton West by-election win

Speaking to journalists early on Friday morning, Mr Sarwar said the victory had been a long time in the making. 

"It's important to stress, in Michael we had a phenomenal candidate. We ran a phenomenal campaign and I'm really proud of the team. But this win is not just two months or six months in the making, this is two years in the making.

"And I think it's important to stress, two years ago, we were 32 points behind the SNP. People were talking about Scottish Labour's survival.

"Two years on for us to win a parliamentary by-election with a swing over 20% to get more than double the SNP vote, I think sends you a really strong signal and message."

He said the result "was even beyond our expectations."

"I think what that demonstrates is that there's something happening in Scotland. There is something happening out there that I think every political party has probably not quite seen the extent of.

"And that is people are sick to the back teeth of the failure, of the decline, of the chaos and the division, and they want change, and Scottish Labour is determined to be that change."

Mr Sarwar said Labour's victory was because they were reaching out beyond their core vote. 

"The Tories are only speaking to their hardcore base. The SNP is only appealing to the hardcore base. We are the only ones trying to reach out and appeal to voters and persuade voters that a different future is possible."

He said he wasn't complacent and acknowledged his party still had "a mountain to climb."

In a statement, Sir Keir Starmer said voters in the constituency had “sent a clear message” that it is “time for change."

He added: “I have always said that winning back the trust of people in Scotland is essential.

“Tonight’s victory is the culmination of three and a half years of hard work and humility on that journey.

“I am grateful to everyone who has put their faith in us today – we will work every day to repay it.

“Voters across Scotland and across Britain want a government determined to deliver for working people, with a proper plan to rebuild our country.

“They want to move on from two SNP and Tory governments that offer only more division, more chaos and more infighting.”

Sir Keir is expected in the constituency on Friday morning. 

READ MORE: Rutherglen & Hamilton West by-election: huge Labour win

SNP Depute Leader Keith Brown said the party was disappointed but put Labour's victory down to Conservative supporters voting tactically. 

“The SNP has run a positive, energetic and engaging campaign - but sadly we were not able to deliver the result we hoped for," he said.

“As the Tories face the prospect of losing all their seats in Scotland, with a devastating result that saw them lose their deposit, it's Sir Keir Starmer’s pro-Brexit Labour Party that benefitted from support from Tory voters."

He paid tribute to Katy Loudon, calling her "a superb candidate."

Mr Brown added: “The SNP will work hard to ensure we are earning, and re-earning, the trust of the people of Scotland in this seat that has switched between the SNP and Labour at every election since 2010, and across the country."