Jeremy Corbyn has seen his odds of retaining the Labour leadership cut after his first head-to-head with his sole challenger Owen Smith yesterday evening (4 August).

The pair mostly clashed on the issue of party unity, with Smith denying that he was part of a coup against Corbyn and warning that the party was "fractured and splintered" under the left-winger.

Corbyn stressed that Labour had won four by-elections, the Mayor of London election and scores of victories in the Houses of Parliament since he succeeded Ed Miliband in 2015, in an election which saw him attract almost 60% of the vote.

"When we work together we win. When we work together we do defeat the Tories," he told an audience of Labour members in Cardiff. "I think as an opposition we've done very well."

Smith used recentl opinion polling to attack Corbyn, citing a survey from YouGov for The Times, of more than 1,700 voters between 1 and 2 August.

The poll put the Conservatives 14 points ahead of Labour (42% versus 28%), with Ukip on 12% and the Liberal Democrats on 8%. "While many in the Labour Party might trust you, Jeremy, the country isn't trusting you and that's got to change," Smith said.

No independent polling was conducted after Corbyn and Smith clash on ITV Wales, but bookmaker William Hill shortened its odds for a Corbyn victory from 1/8 (88% chance of victory) to 1/10 (90%), with Smith a 6/1 (14%) underdog.

"Corbyn has emerged from the opening round with a points lead over his opponent, according to political punters, and seems to be heading for another knockout victory," said Graham Sharpe, a spokesman for William Hill.

The debate came after Corbyn unveiled a 10-point plan to "rebuild" Britain, including a pledge to spend £500bn of public cash on infrastructure, manufacturing and new industries across the UK.

But he was vague on costing details, telling journalists that a Labour government would pay for the commitments by "expanding the economy" and tackling tax evasion.