LONDON, Sept 17: Embattled British Prime Minister Gordon Brown suffered a new poll blow on Wednesday as a survey suggested the main opposition Conservatives are at their most popular since the era of Margaret Thatcher.

Brown is struggling to keep his governing Labour Party in line ahead of its annual conference starting on Saturday, after a junior minister resigned and became the latest to call for Brown to face a leadership contest.

The new Ipsos MORI opinion poll put the Conservatives, whose leader David Cameron hopes to succeed Brown in elections which must be held by May 2010, on 52 per cent, 28 points ahead of Labour on 24 per cent.

The third main party, the Liberal Democrats, were on 12 per cent, according to the survey of 1,017 adults last weekend, just after the latest surge of Labour infighting began.

The results, which follow months of dire ratings for Brown, are the first time the Conservatives have polled above 50 per cent since August 1988, a year after Thatcher’s third general election win for the centre-right party.

Some 54 per cent of those questioned said the Conservatives were ready to form the next government -- up 19 points on last month.

The long-simmering rebellion against Brown’s leadership came to the surface last Friday when a junior government member, Siobhain McDonagh, was fired for calling for a leadership challenge.

Over the weekend, a series of Labour lawmakers also came out publicly for a contest, culminating in the resignation on Tuesday of Scotland Office minister David Cairns.

Possible contenders tipped include Foreign Secretary David Miliband and justice minister Jack Straw, although none has formally declared.

In September 2006, the resignations of seven people in such posts helped push Brown’s predecessor Tony Blair into announcing his plans to stand down.

Brown took over from Blair in June 2007, and initially enjoyed strong poll ratings, but they collapsed after the credit crunch hit and he decided last October against a widely-expected snap election.

Anyone wishing to challenge formally for the Labour leadership has to gain the support of 20 per cent of the party’s lawmakers -- currently 71 people -- and seek nomination before the party conference.—AFP