Lib Dems (UK): What is their constituency?

[YL]

Is it fair to say "the Celtic fringe" + the liberal middle classes that are "too progressive to vote Tory and too "bourgeois to vote Labour"?  People to the left of much of the Labour electorate on social issues but to the right of Labour on economic issues?

This is a complicated question.  Their voting base, especially pre-Coalition, was really quite heterogeneous, and I'm sure some of it was just "plague on both your houses" voters who didn't like either Labour or the Tories for various reasons without being at all liberal in any sense of the word.  (This helps to explain why polls show a significant number of ex-Lib Dems now voting UKIP.)  Of course in their strongholds quite a lot of it was always tactical; their leaflets have always pushed squeeze messages (hence their reputation for dodgy bar charts, which is thoroughly deserved) more strongly than actual policies.

Based on my own experience (and having been one myself once) I think you would find that quite a lot of the urban middle class type of Lib Dem voters (pre-Coalition) wouldn't have  thought of themselves as right of Labour on economics.  (We're talking Blair-era Labour, of course.)  Their beef with Labour would have been on other matters (one of which is four letters long and ends in a Q).

[YL]

Another (more cynical) way to view the LibDems is that to win seats as... varied... as Brent Central/Redcar and Westmorland & Lonsdale/Twickenham at the same time, your only real electoral strategy is one of shameless local level populism, supported by very well targeted tactical votes and protest voters.

I doubt 99% of the Americans ITT understand the reference. Please clarify.

Brent Central is an inner city, ethnically diverse, London constituency.
Redcar is an industrial constituency in the north of England in one of the areas of the UK which has been struggling most economically.
Twickenham is a prosperous suburban area in west/south-west London.
Westmorland & Lonsdale is a largely rural constituency with an economy dominated by tourism.

That all these constituencies currently have MPs from the same party, and one which holds under 10% of the seats in the Commons, is not what you would expect.