ANAS Sarwar has appealed to former Labour voters to “come back home”.
Launching his party’s manifesto for local government, he appealed to supporters who had "held their nose and voted Tory" in previous elections.
"I say to those people directly, Boris Johnson has let you down. Boris Johnson has let the United Kingdom down. Boris Johnson is a corrupt joke and a liar. You don't need to hold your nose and vote Tory anymore, come home and vote Scottish Labour.”
He made a similar appeal to ex-Labour voters who have switched to the SNP: “After 15 years of this SNP government, poverty is on the rise, inequality is on the rise, our communities and our country is more divided than ever, and our local services are being decimated.
“The beloved NHS is on its knees, not because of its workforce, because of the failed management and the failed government. You don't have to wait for the promise of change. We can deliver change right now. Come back home. Vote Labour."
Central pledges in the manifesto include plans to cap bus fares at £1.80, a 50 per cent cut to train fares for the next three months, opposition to the car park levy, and a windfall tax on oil and gas giants.
Speaking to journalists after his speech in New Lanark, Mr Sarwar also made clear his opposition to Labour councillors forming coalitions with Tory or SNP groups.
Though this was ultimately a decision for the party’s ruling Scottish Executive Committee, he said he believed most members of the body agreed with him.
“We’ve had difficult situations in the past where decisions have been made by a Scottish Executive Committee that individual councils haven't liked. But the reality is, it's always been the case that the Scottish Executive Committee would sign off on any agreements.
“And I think it's right for us to say we shouldn't be picking and choosing which is the good versus the bad. Both are bad for our country. Both are decimating local communities. And therefore I think it's right that we see no formal coalition with the SNP or the Tories.”
Asked if any council defying the SEC - as nine Aberdeen councillors did after the last local government - and entering a non-approved coalition would be suspended, Mr Sarwar said: “I'm very confident that there will be a good relationship between our councillors and our Scottish Executive. Things have changed in the Labour Party.”
Mr Sarwar also said he’d expect all of his council candidates to back the manifesto, though he recognised the call for a windfall tax on oil and gas profits could make canvassing difficult in Aberdeen and Aberdeenshire.
“I can understand the sensitivity around campaigning in the North East. And I think it's really important to say we're not saying stop making investments.”
He added: “We're saying it's a one-off windfall tax on profits that have already been made and money that is currently scheduled to go into people's bank accounts rather than go into investments and therefore let’s have that windfall tax to put money directly into people's pockets.”
Mr Sarwar also said his party would oppose the Scottish Government’s workplace parking levy: “The rationale behind that is, particularly in the midst of a cost of living crisis, where you've got fuel prices on the rise, energy prices on the rise, it's incomprehensible, that at the time you're saying to people we're going to tax you to park for work, therefore increasing their cost of living.”
Mr Sarwar said the party were going into the election with the intention of winning, including in Glasgow, where, in 2017, the party were replaced after 37 years by a minority SNP administration.
He said Labour intended to win the city back: “I think if you look at the last five years, what's happened in Glasgow City Council, you can see the difference a Labour council makes.
“Anyone that goes into the city centre can see how neglected it's been. Anyone who looks at the state of our roads, the cleansing can see the difference that a Labour council makes.
“And to be blunt about it, the job of the leader of Glasgow City Council isn't to be a Nicola Sturgeon puppet, just do what they're told to do. The job is to stand up and fight for the city, not stand up and fight for the SNP.”
Responding, the SNP MSP Kaukab Stewart said: "Glasgow knows all too well about the legacy Labour left in the city - the People's Palace left in a state of disrepair and women forced to fight for equal pay thanks to the shameful inaction of the previous Labour administration. Labour have absolutely no credibility in Glasgow.
"It speaks to the Labour Party's ridiculous self-entitlement to think they could run Glasgow forever. Unless they accept their own shameful failings they will continue their slide into even further irrelevance."