Nicola Sturgeon has urged the three candidates vying to replace her as first minster not to lose the trust she has built with Scottish voters, as she clashed with opposition leaders after one contender, Kate Forbes, was accused of “trashing” her own government’s record. Forbes’ description of the Scottish government – in which she serves as finance secretary – as “mediocre” during the campaign’s first televised debate on Tuesday evening resulted in a furious backlash from SNP activists and politicians. The health secretary, Humza Yousaf, the narrow frontrunner who is considered the leadership’s choice to succeed Sturgeon, said the membership had been “hurt” following Forbes’ blunt and often personal attacks on both him and the Sturgeon administration’s record. “These guys knock their pan in to sell the track record of the government that has won us election after election,” he said Challenging Sturgeon repeatedly about the remarks at first minister’s questions on Thursday, the Conservative leader, Douglas Ross, told her that Forbes had “torched” her government’s record. Referring to Forbes’ brutal assessment of Yousaf’s own record in government, in which she claimed that trains were never on time when he was transport secretary, the police were at breaking point when he was justice secretary, and now the NHS had the longest ever waiting lists, Ross joked: “That’s a quote sorted for every Scottish Conservative leaflet going forward.” The Scottish Labour leader, Anas Sarwar, also led on Forbes’ criticisms – unprecedentede for a party which in recent history has been known for its disciplined messaging – asking Sturgeon whether she agreed that “continuity, mediocrity and incompetence won’t cut it”. The STV debate also heard from Ash Regan, the third candidate and outsider in the contest, who claimed “the SNP has lost its way”. Sturgeon, who said she had not watched the debate, insisted the “the record of the Scottish government has been endorsed eight times in eight years by the Scottish people”. While she was careful not to rebuke any one candidate and avoided referring to Forbes by name, Sturgeon went on to warn all three candidates that the current campaign “is actually the relatively easy part”. “Being first minister is hard, it’s tough, it is a massive responsibility. Whoever emerges in the position of first minister and is standing here three weeks today has one overriding task. It’s to govern and it is to serve in a way that inspires the people of Scotland to keep placing trust in us, just as they have done consistently since 2007… because without that trust, nothing else is possible.” Speaking to reporters outside the Holyrood chamber after the session, she denied the leadership contest was heading towards civil war. “It’s almost 20 years since there’s been a leadership election. People are not used to it. But it’s a democratic election, and that’s something to be embraced.” The clashes took place before a second televised debate on Thursday night hosted by Channel 4 news. A poll by Ipsos before the debate found that among SNP voters from the last Holyrood election, 33% said Yousaf would make the best first minister, while another 32% said the same of Forbes, but based on a relatively small sample of 582 people. On Wednesday, Forbes doubled down on her comments, telling reporters: “Last night was all about having the candour and honesty to say more of the same isn’t what Scotland needs – we actually do need change.” But later that evening, at a party hustings in Johnstone, she appearing more ameliorative, praising Sturgeon’s “exceptional leadership”. The social justice secretary, Shona Robison, who is one of Sturgeon’s close allies and is backing Yousaf, told the Daily Record yesterday that Forbes’ comments had upset the wider membership. “I think it’s about the tone and when that steps into what you could describe as a bit of a trashing of the collective record of the SNP government, [it] does not sit well with SNP members.”