Polls have opened in Rutherglen and Hamilton West in a byelection that Scottish Labour leader, Anas Sarwar, says could have a “seismic” impact for his party across the UK. Scotland’s first-ever recall byelection will also be Humza Yousaf’s first significant electoral test since he became SNP leader, and first minister, in the spring. At the beginning of the week, Yousaf downplayed his party’s prospects, saying the contest – triggered after voters ousted Covid rule-breaker Margaret Ferrier – had always been “challenging” and “difficult” for his party. Ferrier was ejected by the SNP after it emerged she had visited local businesses while awaiting the result of a coronavirus test and travelled by train from the Commons back to Scotland after testing positive. She has been sitting as an independent ever since, despite widespread local anger at her behaviour. Speaking to reporters in Cambuslang on Wednesday, Sarwar was in buoyant mood, comparing the current contest to the historic victory of SNP trailblazer Winnie Ewing in Hamilton in 1967. “I believe this has the potential to be a seismic byelection and then as a launchpad as we head towards that next general election,” he said. “We approach that with excitement, we approach that with confidence, but we do it with a hunger and desire to recognise that we have come a long way in terms of persuading people that the Scottish Labour party is back, and we’ve still got a long way to go to earn the trust of the Scottish people, and I’m absolutely determined to do that.” The seat, to the south-east of Glasgow and spanning comfortable suburbs, rundown high streets and pockets of deprivation, has changed hands three times between the SNP and Labour since the 2010 general election. Ferrier first won it in the SNP landslide of 2015, then narrowly lost it to Labour in 2017, before retaking it in 2019 with a 5,230-vote (9.7%) majority. Both frontrunners – Michael Shanks for Labour and Katy Loudon for the SNP – have centred their campaigns on claims they are the only party capable of addressing the cost of living crisis. Shanks, who teaches modern studies at a local high school, said voters were desperate for “a fresh start” after years of limbo with Ferrier. He also attacked the record of the Holyrood SNP government on public services. Loudon has accused UK Labour of “colluding” with Tory policies like the two-child benefit cap, highlighting the impact of austerity locally – including in neighbouring North Lanarkshire, where the Labour-run council was forced on Tuesday into reversing a proposal to close 39 libraries, sports centres and community centres following a public outcry. Loudon, a local councillor, also insisted she was feeling confident. Responding to Sarwar, she said she has spoken to voters who remembered Ewing, who died at the age of 93 earlier this year, and agreed that byelections “can send powerful messages”. “The message I’m hoping people in this constituency are going to send … to Westminster [is] to say we reject your Brexit, we reject your austerity, we reject that you ignore this constituency and Scotland … and send a message to Keir Starmer’s Labour party that we’re not going to put up with your lurch to the right.”