"@chdot, not sure George Kerevan is quite right if he thinks labour lost 4 million votes to UKIP? Nor that UKIP were anti-austerity??"
Well it's impossible to say who (if anyone) people who voted UKIP would have chosen instead if there was no UKIP.
It is clearly the case that UKIP got votes that otherwise could have gone to Lab and Con.
UKIP manages to be different things to different people (in some ways so does the SNP - that is NOT saying that 'the SNP is like UKIP'!). UKIP MPs might well have voted against the welfare cuts.
It's easy to characterise UKIP as 'right wing party' (which essentially it is) and therefore presume it is to the right of the Tories, but the left-right 'spectrum' is no longer that simple/linear.
The Labour Party (at least the Westminster bit) wants to be 'the centre ground' and (if possible) just just left of the Conservatives.
This is because the Lab MPs assume that they won't get elected otherwise. That may be true, but that is because of the electoral system more than how 'right wing' the voters may or may not have become.
In Scotland the SNP has (mostly) lost the Tartan Tories tag and is now seen by some as a 'left wing party' - and is getting elected.
Consequently there are those who say 'Scottish voters are different' and others who assert that the 'British electorate' doesn't diverge sharply at the Border.