British Prime Minister David Cameron and his main election rival Ed Miliband faced a prime time television grilling, kicking off a tight race for the May 7 election.
A snap Guardian/ICM poll of viewers showed 54 percent believed Cameron of the centre-right Conservatives put in the strongest performance, compared to 46 percent for centre-left Labour leader Miliband.
Under a format agreed after months of negotiations, the two politicians were questioned separately and did not debate with each other.
Both leaders faced tough interrogations by veteran interviewer Jeremy Paxman -- known for his withering glares and quizzical raised eyebrows -- which left Cameron looking uncomfortable, while Miliband took a more combative approach.
Asked about claims from critics that he is a "north London geek" lacking the inner steel to represent Britain in the world, Miliband hit back: "Am I tough enough? Hell yes, I'm tough enough."
Cameron, meanwhile, was questioned about where austerity cuts would fall, his plans to hold a referendum on Britain leaving the European Union and his disclosure this week that he would not stand for a third term if re-elected.
"You are going to have to make this huge choice in 42 days' time," he said. "What I have learnt in the last five years is that nothing you want to do will work without a strong and growing economy."
The pair were also questioned by members of the studio audience.
Commentators say Cameron's Conservatives did not want a head-to-head debate in the belief that a lacklustre performance in TV debates during the 2010 election campaign contributed to their failure to win outright.
The 95-minute programme came hours after parliament held its last day of business before shutting down ahead of the polls, signalling the real start of an election campaign which has been simmering for weeks.
- Stalemate in polls -
The Conservatives and Labour are neck-and-neck in opinion polls on 34 percent, according to an average calculated by the UK Polling Report website.
Both will be hoping that the TV session could help shift this long-term stalemate.
According to the ICM polling, Miliband fared better when it came to floating voters -- 56 percent of those who said they could still change their mind said they would now back Labour compared to 30 percent for the Conservatives.
The overall ICM survey was based on online interviews with 3,650 adults.
The Conservatives, in a coalition government with the centrist Liberal Democrats for the past five years, are focusing their election campaign on the economy.
Britain has emerged from recession under the coalition but also faced steep austerity cuts in areas such as welfare.
The party once led by Margaret Thatcher is appealing for voters to give them another term in power, this time with a clear majority, to deliver on their "long-term economic plan".
Labour accuses the Conservatives of favouring the wealthy in society and has pledged to do more to help struggling middle and lower income voters.
In office between 1997 and 2010 under Tony Blair and Gordon Brown, they would not hold the referendum on Britain leaving the European Union which the Conservatives say they will call by 2017 if they win.
Unlike many European countries, Britain does not have a long history of televised debates during its election campaigns -- 2010 was the first year they took place.
Three other election TV events featuring different line-ups of party leaders are due to take place on April 2, April 16 and April 30.