Anas Sarwar has claimed that victory in a key by-election can hand Scottish Labour momentum to take the party up to the Holyrood elections in 2026.

The Scottish Labour leader said that securing victory in the by-election would help him begin to “earn the right for people to regard me as being competitive to become first minister come 2026”.

He said residents in Rutherglen and Hamilton West can now get closure after “three years” without “adequate representation”.

The constituency’s by-election has been confirmed for October 5 after the seat was vacated by former SNP MP Margaret Ferrier following a successful recall petition after her conviction for breaching Covid restrictions in 2020.

Read more: Anas Sarwar accuses Humza Yousaf of pursuing 'Green extremism'

It is expected to be an important battleground ahead of the UK general election, which is expected next year, with the SNP’s Katy Loudon taking on Labour’s Michael Shanks.

The seat is regarded as Labour’s to lose and failure to secure the seat and double its tally of MPs north of the Border would stunt Sir Keir Starmer’s confidence of securing a big victory at the next general election.

Welcoming the by-election date, Mr Sarwar said: “I think it’s fantastic that we finally have a date and that it’s going to be as soon as practicably possible from this moment, given than this community has not had adequate representation for the last three years.

“That has been a failure, of course, on Margaret Ferrier’s part, but actually a failure on the SNP’s part as well.”

Read more: Anas Sarwar aims to deliver economic strategy as next first minister

On his party’s chances of winning, he said: “This is a significant by-election. There’s no escaping that, but we are not complacent.”

Speaking on how a win would impact the party ahead of next year’s general election, he said: “We’ve got to continue that momentum, but that momentum is there for a purpose.

“For far too long now the people of Scotland and the UK have been let down by two failing governments.”

Read more: Anas Sarwar warns income tax levels 'hammering families'

Mr Sarwar previously hit out at First Minister Humza Yousaf’s leadership so far, as he said his opponent was “not up to the top job”.

But he insisted that a win at the upcoming by-election will show that he can be considered for the job of first minister in the 2026 Scottish Parliament elections.

He said: “I think we have earned the right to be listened to again. We’re now earning the right, I think, to be supported again, but we’ve still go a long way to go.

“And I want to earn the right for people to regard me as being competitive to become first minister come 2026.

“We’re making good progress on that but that’s the ultimate end game, it’s not just delivering a UK Labour government but delivering a Labour government here in Scotland.”

The SNP’s deputy Westminster leader, Mhairi Black, said: “This is a remarkable blunder from Anas Sarwar who has admitted that, for Labour, this by-election is not about what’s best for the people of Rutherglen and Hamilton West, but more about how it can benefit the Labour’s party political interests.

“In contrast, Katy Loudon is the only candidate ready to stand up for the people in Rutherglen and Hamilton West who’ve faced 13 years of relentless Tory austerity, now supported by Starmer’s Labour Party.

“Any suggestion that a Labour MP would represent the people of Rutherglen and Hamilton West is laughable considering their ardent support of the most brutal of Tory policies: the two-child cap, the rape clause, and the damaging Brexit they’ve imposed on Scotland against our will.

“Labour simply can’t be trusted to stand up for Scotland. If they hope to ever gain the trust of voters, they need to start by renouncing their support of Tory policies and begin supporting Scotland’s democratic right to choose our own future.”