Angela Eagle has dropped out of the race to lead the Labour party after securing fewer nominations from MPs and MEPs than Owen Smith.
Her withdrawal on Tuesday afternoon cleared the way for a head-to-head battle between current leader Jeremy Corbyn and Welsh MP Smith.
There had been pressure from the Parliamentary Labour Party for a single candidate to run against Mr Corbyn.
Ms Eagle said: “I’m withdrawing from this race and supporting Owen.”
Ms Eagle added she would support Mr Smith’s bid for the leadership with all of her “enthusiasm and might”.
Despite a lack of support from his fellow Labour MPs in Westminster, a poll of Labour party members has shown Mr Corbyn would secure around 54% of the vote.
People who wish to vote in the election have until 5pm on Wednesday to pay their £25 fee to register as a Labour party member.