MercoPress. South Atlantic News Agency

Labor setback in Glasgow, political earthquake for Brown

Labour lost one of its safest seats in Glasgow

Critics have increased the pressure on British Prime Minister Gordon Brown after Labor's defeat in the Glasgow East by-election, but colleagues have leapt to his defense

The head of one of the UK's top unions has demanded a leadership contest, while Tory leader David Cameron has called for a general election. But Chancellor Alistair Darling urged Labour to "rediscover the conviction" on which it won three elections. Members are at Warwick University for the party's National Policy Forum. The Scottish National Party won Glasgow East - previously considered one of Labor's safest seats - by 365 votes, achieving a 22.54% swing. John Mason, the victorious candidate, said the result was "not just a political earthquake, it is off the Richter scale". It followed Labor's recent loss of the Crewe and Nantwich seat, the London mayoralty and poor results in local elections. Paul Kenny, general secretary of the GMB union, said the party needs to take a "strong decision" on whether to back Mr Brown or replace him with an autumn leadership election. "The MPs have got to have the courage of their convictions - if they've got them," he added. "They've got the constitutional right under Labour party rules, and my advice to them is get on with it." But BBC political correspondent James Landale said MPs' summer recess would make it harder to foment a leadership plot. Mr Cameron demanded that the prime minister call a general election after he returns from his summer holiday. "I think we need change in this country, and that's how change should come about," Mr Cameron said. However, Liberal Democrat leader Nick Clegg said it was not "time to play politics with people's lives" by calling an election "when so many people are worried about the price of a loaf of bread, how to fill their car with a tank of petrol". Mr Brown, who has to call a general election by June 2010 at the latest, appeared to suggest he would not go to the country soon.