It's difficult to know where to start with the Scottish Liberal Democrat collapse in Scotland.

We have been here before at the Scottish Parliament election in 2011, local elections in 2012 and European elections in 2014 but the collapse is now accompanied by a huge loss of seats and votes across Britain.

The party won just 7.5 per cent of the vote in Scotland - even lower than in 2011. But that is just ahead of 7.7 per cent for the UK as the party struggled to retain seats in double figures. The LibDems experienced hundreds of lost deposits and this saw them finish third and fourth behind the Greens and Ukip in many constituencies. Their performance in the English local elections may also show serious losses of support to its local electoral base.

Key figures including Danny Alexander, Charles Kennedy, Simon Hughes, Ed Davey and Vince Cable lost their seats. Nick Clegg, who resigned as leader yesterday, held on, but the party now faces a major crisis in Scotland and across the UK driven by losses of support and in leadership. Where does it go from here, given it has been picked apart by different parties in different parts of the UK?

Attempts to shore up the party's position by claiming its relevance as centrist coalition partner to either the Conservatives or Labour fell down during the night as its representation sank to the level of 1970. All the party's growth and consolidation from the 1980s onwards were undone in one night, following its five-year coalition with the Conservatives.

The party approached this election by defending its record in government - delivering some of its policies and preventing the Tories from implementing theirs. It also sought to differentiate itself from the Conservatives and from Labour and tried to concentrate its campaigning on the 57 seats it had won in 2010.

Moreover, the party spent a fortune on its incumbent MPs, with party funding from HQ contributing to the delivery of huge amounts of election literature in its 2010 seats. This was evident in my own seat of Edinburgh West, where I would receive three pieces of literature a day and often material on consecutive days.

Here, the party even succeeded in pushing up its vote by a couple of thousand in an attempt to stave off the SNP advance. However, the material support for incumbents failed to work in most seats - take North East Fife or West Aberdeenshire and Kincardine as good examples. Their voters were buried in LibDem leaflets, newspapers and letters and the party targeted Conservative tactical defectors to help it stave off the SNP. This was most prominent in Gordon, but the tactic failed spectacularly. Its tactical efforts failed in England and Wales too.

The LibDem claim was that their hard-working incumbents had personal votes and reputations that would enable them to bypass the collapse in their national levels of support. However, as it turned out, few MPs in the party could buck the trend and some - Robert Smith in West Aberdeenshire and Michael Moore in Berwickshire, Roxburgh and Selkirk - dropped down to third place behind the SNP and Conservatives. Moore's vote fell by 26.7 per cent.

To some extent, the incumbents were on their own as local campaigners but they received campaign and financial support from the central organization in London, in the tens of thousands. In Scotland, some of the more prominent MPs were stuck defending their constituencies but quite a few turned out with hyperactive Willie Rennie to campaign for each other: Charles Kennedy and the retiring Menzies Campbell both turned out to help colleagues. The party fought its seats like a by-election but saw dramatic falls in its support in most places.

In terms of share of the vote, the party did worse in 2015 than in 2011 and the electoral system was even more punishing. Its only first-past-the-post seats in 2011 were for Orkney and Shetland, a result which has been replicated this time around though, at this election, the party only just clung on to the islands seat it had held since 1950. Its only Scottish MP is now Alastair Carmichael who has also became a major figure in the UK party as so many colleagues fell by the wayside.

One final point to ponder. The LibDems have lost so many seats in the UK that the vast majority of the party's parliamentarians are actually members of the House of Lords, not elected members of the Commons. That presents a major dilemma for the party.