This is absolute bollocks - all we know is that Labour's share of the vote is up massively since the general election, Lib Dems is down and Tories even more so. The rest of it is pure conjecture on your part.if there were a general election you would see the turnout rise significantly. the fact that Labour gained so little in terms of actual votes shows there was no protest against the government. someone said its a no score draw, that about sums it up.
If I could be arsed, I'd trawl through NSC for some by-election results just before the general election where the vote did something like this, but with the Tory party performing well. I bet "no score draw" is absolutely not how you'll have summed it up.