The Scottish Labour leader, Anas Sarwar, has launched a detailed attack on Nicola Sturgeon’s record as he moved to exploit the Scottish National party’s disarray after her resignation. Sarwar told Labour activists and MSPs that Sturgeon’s government had grown “tired and arrogant” after 15 years, and had left Scotland facing record NHS waiting lists, councils in crisis, record drugs deaths, teachers’ strikes and transport links in chaos. “The truth is the SNP has nothing left to offer our country. They promised hope but have given us arrogance,” he told delegates to Scottish Labour’s spring conference in Edinburgh, which began 48 hours after Sturgeon’s shock announcement she would quit. The SNP “failed to fix the roof when the sun was shining”, he said. As senior SNP ministers prepare to launch their leadership bids over the next few days, Sarwar directly attacked the records of those expected to stand – a clear signal Labour believes Sturgeon’s departure offers an unexpected opportunity to reverse 15 years of decline in Scotland. “I have never been as confident as I am today that change is possible – that Labour governments are possible. That our opponents’ time is up,” Sarwar said, in a speech hardened up after Sturgeon’s resignation. He accused Humza Yousaf, who is expected to stand, of being “the health secretary who has delivered the longest waiting times in our history”. Angus Robertson, the bookmakers’ favourite, he described as “the air-miles culture secretary jetting around the world while cutting services here at home”. He said Kate Forbes, another widely tipped leadership candidate, was “the finance secretary who has decimated local communities”. Keith Brown, an outlier who may also stand, was “the justice secretary who won’t give police officers the equipment they need”. He acknowledged that a generation of younger Scots had only lived with the SNP in government in Scotland. He urged both SNP supporters and floating Conservative voters to see Labour led by Keir Starmer as the party best placed to replace the “morally bankrupt” Tory government at Westminster. “We know you dream of a brighter future,” he said to SNP voters, claiming Labour was committed to overhauling the UK’s constitution and Westminster parliament. “It’s a dream we share. Because this isn’t as good as it gets. You deserve better. Scotland deserves better.” The latest Scottish Election Study survey, conducted just before Sturgeon’s resignation, finds that Labour has gained support since November, jumping from 23% to 27% on Holyrood voting intention, bringing the party almost level with the SNP on 29%. In an effort to set out Labour’s stall before the next election, Sarwar announced Labour would seize abandoned homes for £1 and offer homeless people £25,000 to renovate and live in them; create a new “Amazon tax” to greatly increase business rates on internet-only retailers; and pledge to purge the NHS of its “bloated” bureaucracy. Also on Friday, John Swinney, Scotland’s deputy first minister and one of the SNP’s most experienced and respected figures, urged leadership candidates to “anchor the SNP in the mainstream of Scottish politics” by focusing on what matters to voters, as he ruled himself out of the contest. Yousaf told BBC Scotland he was “seriously considering” standing. He added: “If I did get selected by the membership then of course it wouldn’t just have an impact on me, it would have an impact on my family. I have got two young girls and a wife and a family and therefore I have got think about the impact on them too.” After a meeting of the party’s national executive committee on Thursday night, candidates will have until next Friday to put their names forward. A six-week contest will follow, with ballots of 100,000-plus members closing on 27 March.