Far-right populists are not the answer to the UK's political problems, Scottish Greens' co-convener Patrick Harvie has said, as the party launched its European election manifesto.

With a slogan urging voters to "choose hope over hate", the Greens are hoping to secure their first MEP north of the border at the polls on May 23.

Harvie was joined by fellow co-convener and lead European candidate Maggie Chapman for the launch at West Brewery in Glasgow.

Speaking to STV News, Harvie highlighted Green gains at last week's English local elections as a template for success, with the Green party adding 194 councillors.

The Glasgow MSP said: "Politics can be quite polarised at the moment and I think that's a sign of the way very many communities feel neglected and ignored by the political mainstream, by the centre-ground status quo parties.

"But turning to hatred, fear, division, xenophobia and the far-right populists, that is not the solution.

"If you look at what happened with the local elections last week down south and in Northern Ireland, actually the Greens have made a massive increase in their number of councillors.

"But not just that: all the pro-Brexit parties were down hugely, and it was those challenging this notion that Brexit is a solution to our problems, they're the parties that did really well, got more people elected.

"I think the same thing can happen again in the European Parliament elections."

He added: "Let's send a message to Theresa May and to Jeremy Corbyn that some dodgy stitch-up behind closed doors, to force through a Brexit that Scotland didn't vote for and a lot of people throughout the UK have turned against - that is not the solution to the country's problems either."

Harvie described a "Green wave of support" building in the UK and across Europe, with issues like the climate and environmental breakdown "so much further up the agenda".

He also indicated his party, which backs Scottish independence, would call for a second independence referendum by 2021 even if Brexit doesn't happen.

"Even if the UK isn't ultimately dragged out of the European Union, we've already seen a fundamental assault against the devolution settlement," Harvie told STV.

"We no longer have the Scottish Parliament that we thought we had when we voted for it 20 years ago, when it was first sitting in Edinburgh.

"We've seen the UK Government willing to retrospectively veto the powers of the Scottish Parliament on a devolved matter just because we do something that they don't like in the Tory cabinet.

"So, we very clearly know that circumstances have changed profoundly - not just the way Scotland has been treated on the Brexit issue, but the way the devolution settlement itself has been shot through by a UK government that simply has contempt for Scotland."

The Green MSP continued: "That change of circumstances does mean, to me, that the people of Scotland have a right to make their own choice and I hope that happens sooner rather than later."

Lead candidate Chapman raised the prospect of post-Brexit trade deals with countries like the US impacting on Britain's public services.

She told STV: "Theresa May has been talking about trade deals with the United States that would see the wholesale privatisation of the NHS but also likely our education, and transformation of our agriculture and other life-sustaining parts of Scotland's economy.

"That's not what we want and it's not what the Scottish people voted for three years ago."