Her face was unforgettable, lips drawn into a tight line, fury radiating from her eyes. It was 2010 and this former lifelong Labour voter, a friend of mine, had switched to the Liberal Democrats in the General Election, swept up in Cleggmania.

After all the lefty-sounding promises Nick Clegg had made – abolishing tuition fees, introducing a mansion tax, opposing austerity policies – she’d given him her vote on trust.

Now she was magisterially angry. She could not believe that Clegg was helping the Conservatives form a government. The Clegg-Cameron dynamic, a pair of public-school contemporaries smiling complacently in the Downing Street rose garden, made matters worse. It made their partnership seem like it was the most natural thing in the world.

It cut no ice with my friend that the LibDems could hardly campaign for collaborative politics only to say “we didn’t mean you” when the electoral maths pointed towards a coalition with the Conservatives – especially not in the middle of an economic crisis. If the LibDems had refused a coalition, forcing an unstable minority Tory government on the country, it would have meant months of political deadlock and another General Election which the Tories would have won outright.

But my friend was not interested and frankly, none of it mattered in the end anyway. If Clegg and co had made life visibly harder for the Tories, then perhaps things would have been different. Instead they were blasted as supine coalition partners after not just abandoning their tuition fees pledge, but acquiescing in eye-watering fee hikes.

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In fairness to them, the LibDems did block some Tory excesses, such as inheritance tax cuts for millionaires, regressive climate change policies, oh, and a referendum on Britain’s membership of the European Union – but the damage was done and in 2015, they lost 49 of their 57 seats.

That was then; this is now.

It looks as if England and Wales have largely forgotten the LibDems’ record, or forgiven them for it.

In last Thursday’s local elections, the LibDem story arc was one of redemption. The party added 405 councillors, not far short of Labour’s 536.

The question is whether that resurgence will be replicated at the next General Election and whether Scotland will follow suit.

General Election polls still show the party on an anaemic 11 per cent, but much like their spectacular by-election wins in Tiverton and North Shropshire, the local election results underline the formidable threat they pose to the Tories in certain constituencies. Some blue seats will almost certainly turn yellow. With Labour looking like it could fall short of a majority in 2024, and LibDem leader Ed Davey ruling out a coalition with the Tories, a Labour-LibDem coalition government at Westminster is now a realistic prospect.

So the LibDems’ days in the wilderness are over. The Cameron-Clegg era feels sepia-tinted now, as if it happened in a different age (constitutional turmoil, a pandemic and two appalling Prime Ministers will do that). The LibDems were also the most firmly anti-Brexit of all the parties and have been vindicated for that.

Above all, voters are impatient to get shot of the Tories and seem happy to back whoever is best placed to help make that happen. The Liberal Democrats are winning support in traditionally true-blue constituencies by ruling out a coalition with the Conservatives and hinting at one with Labour. That strategy looks outlandish on paper but it shows just how much trouble the Conservatives are in.

While the LibDems are not consciously shifting left so much as capitalising on the anti-Tory zeitgeist, their obvious preference for Labour over the Tories does put them firmly back on the centre left of politics as they were in their more successful days under Paddy Ashdown and the Scottish social democrats Charles Kennedy and Menzies Campbell.

Sir Keir Starmer for his part has this week conspicuously left open the possibility of a LibDem-Labour coalition too. This sends a clear message to canny tactical voters that the more Labour and LibDem MPs there are, the better chance there is of ousting the Tories.

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What about Scotland? Well that message could spell trouble for the SNP. Labour has a number of SNP seats in its sights, but the LibDems too will be hoping to capitalise on a tactical anti-Tory vote as the main challengers to the SNP in East Dumbartonshire (Jo Swinson’s old seat, where they are a close second) and Ross, Skye and Lochaber (a tougher prospect).

But of course a Scottish election is never just about the parties, but the broader story of our future as a nation, and a possible Labour-LibDem link-up has salience here too. Proportional representation would likely be the LibDems’ price to support Labour in government, and if the UK voting system is made more proportional, it will make Tory Westminster governments less likely, reducing one of the big push factors for independence.

A contrary Keir Starmer has said he won’t have PR in Labour’s manifesto or do any deals to bring in PR “going into the election or coming out of the election” – worried, perhaps, about how much the Tories could misrepresent the policy after they mischievously attacked a supposed “coalition of chaos” between Labour and the SNP in 2015.

But things are different now. For one thing, the Tories are responsible for the worst political and economic turmoil most of us can remember so a coalition of chaos might be a nice change. Secondly, coalitions in recent British politics have all been far more stable than any recent Tory government. Thirdly, PR is now Labour Party policy, passed by conference, even if it’s not in the manifesto. And fourthly, the LibDems are unlikely to budge on it as a coalition demand. Would Starmer really forego the chance of forming a stable government in order to block one of his own party’s policies? Doubtful.

So change looks like it’s coming at the next election. My friend may not vote LibDem again, but others will. Old norms are being overturned. After years when Scotland’s politics was static, it’s entering a more dynamic, molten phase.

For once, it will be an election worth staying up for.