Date of forecast: 28 April 2015
Days till the election: 9

Inputted current average poll shares
Con: 34%
Lab: 33%
LD: 8%
UKIP: 14%
Others: 11%

Forecast GB Vote Shares (with 95% Prediction Intervals)
Con: 35% (31% – 39%)
Lab: 32% (28% – 36%)
LD: 10% (6% – 13%)
UKIP: 13% (9% – 17%)
Others: 10% (9% – 12%)

Forecast Scotland Vote Shares (with 95% Prediction Intervals)
SNP: 48% (44% – 55%)
Labour: 27% (23% – 31%)

Forecast GB Seats (with 95% Prediction Intervals)
Con: 291 (249 – 333)
Lab: 258 (217 – 297)
LD: 25 (16 – 34)
SNP: 53 (45 – 57)
PC: 3 (2 – 3)
UKIP: 3 (3 – 4)
Grn: 1
(May not sum to 632 due to rounding of sums of probabilities.)

Central forecast: Con short of a majority by 32
(Criterion for majority now changed to 323 not 326, assuming Sinn Fein win 5 seats and do not take them.)

Probabilities of key outcomes
Con most votes: 78%
Lab most votes: 22%

Con most seats: 75%
Lab most seats: 25%

Hung Parliament: 90%
… with Con largest: 65%
… with Lab largest: 25%

Probabilities of predicted government outcomes:
(See here for explanations and assumptions)

Con majority: 10%
Con+DUP: 7%
Con+LD: 19%
Con+LD+DUP: 15%
Con largest, Lab+SNP+DUP+other left maj: 6%
Con largest, but Lab+SNP+other left maj: 11%
Con largest, but Lab+SNP maj: 6%
Lab largest, Lab+SNP maj: 8%
Lab+LD+DUP+SDLP+PC+Grn+Hermon: 6%
Lab+LD+DUP: 5%
Lab+LD: 5%
Lab+DUP: 1%
Lab majority: 0%

(Probabilities may not sum due to rounding)