Hopkirk
That was my initial line on IG.
But with both the Tories and Labour being percieved as extremists, the public might vote for a middle ground party.
If IG get 50-60 MPs, then they are coalition candidates after a General Election. Disaffected Tories who cannot bring themselves to vot Labour would vote IG, and so would Labour supporters.
Unlike the Gang of Four (SDP) who were all Labour defectors, IG is cross-party, so would have a bigger pool of potential voters.