British politics will live a historic moment tonight when leaders of the three major national political parties meet in a live televised debate, which is common in Western democracies but unprecedented in the United Kingdom. The Labour candidate and ongoing Prime Minister Gordon Brown, the conservative frontrunner, David Cameron and Liberal Democrat Nick Clegg will discuss questions of domestic policy for ninety minutes at 8.30 tonight. This first debate will be held in Manchester, it will be broadcasted by ITV and is expected to reach an audience of 20 million people. Before the May 6 election ,candidates face off in live and direct on two other occasions: on Thursday, 22nd discuss foreign policy on Sky and on the 29th they will address the issue on the BBC's hottest campaign : the economy. Conservative David Cameron, the most telegenic of the three candidates, is priori favored to win the audience, but is also at the most risk because he is ahead in the polls and runs the risk of losing votes if he makes a mistake of any sort that may question that leadership. Gordon Brown does not work well on television, he is expected to address only eight questions in total, he may be encouraged by their ability to master the details of each case. And the liberal Nick Clegg has a golden opportunity to promote themselves to the British and overcome one of its biggest political obstacles: the vast majority of voters do not know who he is. All three candidates seem nervous about the stake. Brown has been rehearsing with a heavyweight, Alistair Campbell, former director of communications for Tony Blair and British media says it is costing to meet the agreed standards and not exceed the maximum time that has to give their answers. Lord Mandelson, brain in the shadow of Labour's strategy in recent months, publicly advised him to be "himself", the strengths and weaknesses Brown that the British already know, and avoid falling into provocations that Cameron raises. Other advisers appear to believe that Brown should seek a death blow with his fist thats dialectical speaking the day that Tony Blair gave up his leadership and has not just appeared in the parliamentary debates in the Commons. David Cameron has declared he is "nervous" before the first of three events that may end up deciding elections that polls prediction is tight. But Brown is more comfortable on camera and mental quickness makes him a dangerous opponent in any debate. For Clegg, all are opportunities. Nobody knows what he will be like in the debates because the prime minister has only ever been Conservative or Labour. But his presence will at least justify himself with 20% of British voters tend to support the British liberals at the polls even knowing that because of the electoral system the vast majority of those votes are worthless.