According to this, Labour needs a 0.77-point lead in order to catch up the Tories in terms of seats (with a uniform swing of 1.59). That's bad, but not too bad.
They need a 7.22-point lead to win an absolute majority. Tories only need a 3.29-point lead. Now THAT is bad.
2 things that could mitigate this problem:
1) A Lab almost-majority is probably more stable than a Con almost-majority. SNP, Plaid, LD, Green will certainly be bigger and probably more cooperative than DUP/UKIP.
2) A large swing to Labour is likely to produce more seats than uniform swing would suggest. It happened this time (Labour's vote was more efficient than often predicted), and their Liverpool/North London vote shares are pretty much at their ceiling; the swing would have to be from elsewhere.
