IT wasn't just a bad result for the Liberal Democrats, it was a "crushing" one, as a waxen-faced Nick Clegg admitted in his resignation speech.

From winning 57 seats in 2010 to clinging on to a mere eight, Clegg's party was proportionately the biggest UK loser of the night.

And outside the English South West, where the Tories over-ran a series of LibDem strongholds, the losses were felt most keenly in Scotland.

The agony was partly down to the rejection of so many well-known incumbents.

Despite their reputation for loyalty to local MPs, Highland voters didn't think twice about ejecting veterans such as Charlie Kennedy, John Thurso and Sir Robert Smith, while no amount of pork barrel projects in Inverness could save Danny Alexander.

Former minister Jo Swinson was another big casualty in East Dunbartonshire, and former Scottish Secretary Michael Moore was taken out in Berwickshire, Roxburgh & Selkirk.

The other source of grief was that, in campaigning terms, the LibDems did a lot right.

They started working early, had a clear objective, and ruthlessly focused their efforts.

Although they lost 47 of their 59 deposits in Scotland, the LibDems held their deposit in their priority seats, where they also suffered smaller than average declines.

But in the end they were simply overwhelmed by the SNP surge.

The LibDems lost 10 of the 11 constituencies won in 2010, just holding on in Orkney & Shetland, and saw their total votes halved from 465,470 to 219,675, while vote share fell even more precipitously, from 18.9 per cent to 7.5 per cent.

It was a gutting end to a process that began shortly after the 2011 Holyrood elections, when the party lost 11 of its 16 MSPs.

That result was a wake-up moment. Under new leader Willie Rennie, the party decided to fight a wholly defensive campaign in 2015.

There would be no attempt to gain seats. That was a dream for another day.

Instead, everything would be geared to holding what the party already had.

Every election effort was subordinated to saving the Scottish Liberal Democrats' Westminster eleven.

In the 2012 council polls, most campaigning was in the 11 seats.

In the Holyrood by-election for Aberdeen Donside in 2013, the only campaigning was in areas which were also in Gordon - the rest of the seat was ignored.

Likewise in last year's European elections, when all efforts were put into the 11.

The referendum also saw LibDem candidates in the 11 seats position themselves as the local cheerleaders for the Unionist campaign.

The party then used ballot box counts to see where the No vote was strongest and bombarded voters with leaflets urging a tactical vote against the SNP.

Although tightly focused, the campaign was five times bigger than any previous one in Scotland.

Rennie was in charge, assisted by campaigns director Adam Stachura, a fast-talking data geek with a well-thumbed copy of Sun Tzu's Art of War in his Edinburgh office.

There was also input from Ryan Coetzee, the UK party's director of election strategy, and cash from no-hope English seats sent north to save Scottish ones.

Party campaigners had few illusions - they knew the election would be grim.

But even last week, senior figures hoped to return a handful of MPs.

It was not to be. As former leader Lord David Steel said on Friday, the entire party's fate was sealed in the Coalition talks of 2010 when "too many mistakes" were made, most obviously the U-turn on tuition fees, resulting in a crippling loss of trust.

The voters' revenge had been in the post ever since. On May 7 it finally arrived.