A new poll puts Labour nine points clear of the Conservatives, a lead which would double Gordon Brown's Commons majority if replicated in a general election.
The YouGov survey for Friday's Daily Telegraph newspaper put the prime minister's party on 41 per cent, up three points on last month.
Meanwhile the Conservatives are down three on 32 per cent and the Liberal Democrats up one on 16.
It is the best YouGov result for Labour since the outbreak of the Iraq war in 2003.
A similar election result would give the government a 134-seat majority in Parliament.
Conservative leader David Cameron's personal ratings also continue to suffer, with his 43 per cent approval rating of six months ago now down to 27 per cent.
In contrast Brown's has risen and he is now 18 points ahead of Cameron on who voters feel would make the best prime minister.
