The Scottish Greens would be “willing to have the conversation” about a formal coalition with the SNP, their co-leader Patrick Harvie has suggested, as the party set out detailed plans for a green economic recovery from the pandemic which it believes would create at least 100,000 jobs and ensure that those who can best afford it contribute most. With the party predicted by some polls to double its five MSPs in May’s Holyrood elections and describing the manifesto as “a programme for government” for the first time, Harvie downplayed speculation that the Scottish Greens could enter a coalition with the SNP if they fail to win an outright majority, allowing Nicola Sturgeon to still claim a mandate for a second independence referendum. Launching the manifesto document on Wednesday morning in Glasgow, Harvie said: “There are Green parties in coalition in a number of other European countries. We do aspire to take a role in government. It’s for the people to decide what the election result is and it will be for the biggest party to decide if they want to talk with others. “If we were asked, I suspect lot of people in party would be willing for us to have the conversation but there are really massive issues that I don’t think the SNP are grappling with yet, like the future transition away from fossil fuels, like the land reform agenda that they haven’t taken forward.” Listing the ways that the Green party had successfully influenced the SNP – such as free school meals for primary children, the eviction ban during the pandemic and public sector pay in the most recent budget – Harvie said: “We’ve shown over the part five years, whether you’re in government or opposition, if you put forward good constructive ideas and make the case for them you can make a difference.” If a pro-independence majority of MSPs is returned on 6 May, the continued refusal by the UK to discuss a second independence referendum “would be politically untenable”, Harvie added. “It is possible it could be legally challenged as well. We would be open to exploring that.” Proposing an infrastructure investment plan, including public transport and renewable energy projects, which could create more than 100,000 new jobs as the country transitions away from oil and gas, the co-leader Lorna Slater insisted that these initiatives must include commitments to keep jobs in Scotland. “We simply can’t hand our renewable resources to multinational corporations and hope they do the right thing,” she said, adding there must be conditions – “specific numbers of jobs, amounts of money going back into local communities and commitment to using Scottish supply chains.” Slater, an engineer, said she was working on a turbine built in the port of Dundee, welded in Fife and made with steel from Motherwell. “We can build large structures in Scotland,” she said. “It is just the political will to write those clauses in the contract.” The manifesto also proposes a windfall tax for companies that have most profited during the pandemic, such as online retailers and big supermarkets, and a 1% millionaire’s tax on all assets above a £1m threshold – including property and pensions, which the party said would apply to the richest 10% in Scotland. Harvie said he would not work with Alex Salmond’s newly formed Alba party, and that he “doesn’t expect him to be in parliament anyway”.