The Hartlepool by-election will be “really, really challenging” for Labour, the party’s Scottish leader Anas Sarwar has said.

Mr Sarwar said both he and Sir Keir Starmer are working to build Labour as a “credible alternative”.

He spoke to journalists after attending a drive-in rally in Glasgow with former prime minister Gordon Brown, ahead of polling day in the Scottish Parliament election on Thursday.

He was asked about upcoming Westminster by-elections in Hartlepool – a seat which Labour held in 2019 – and Airdrie and Shotts, where voters will choose a new MP next week.

Mr Sarwar said: “Hartlepool is a really, really challenging seat.

“I don’t think we can escape the fact that there was a huge Brexit Party vote in the last election, that poses its own challenge.”

One recent opinion poll suggested the Tories have a double-digit lead over Labour in Hartlepool, which has been won by Labour since the seat was created in 1974.

Mr Sarwar, who became Scottish Labour leader in February, said the election campaign in Scotland had given him the chance to present himself in a more “energetic and forceful way”, while a UK-wide general election is likely to be a number of years away.

He said: “Keir, like every leader, has not been able to do large events and he’s not even had an opportunity to shake a single hand since he’s been a leader due to the pandemic.

“I hope we get a good result in Hartlepool.

“But how we rebuild the country – we rebuild the country with humility, with honesty, with authenticity, with energy to demonstrate we are building a credible alternative.

“That’s what I’m doing in Scotland and that’s what Keir is doing across the UK.”

He said Labour is running an “energetic” campaign in Airdrie and Shotts with a “phenomenal local candidate”.