Britain's Justice Secretary David Gauke says he will quit if Boris Johnson becomes prime minister.
Gauke, who has served in Prime Minister Theresa May's cabinet since she took office in June 2016, said he would not be able to serve under the former foreign secretary if he pursues a no-deal Brexit.
As the Tory leadership contest enters its final 48 hours, the prominent no-deal critic told the Sunday Times that crashing out of the European Union would lead to national "humiliation".
"Given that I've been in the cabinet since Theresa May came to power, I think the appropriate thing is for me to resign to her," Gauke said.
The paper also reported that up to six Tory MPs are considering defecting to the Liberal Democrats should Johnson beat his rival Jeremy Hunt and enter Number 10 - leaving him with no majority in the Commons.
The ballot for the Tory leadership race will close on Monday, with the result announced the following day.
Johnson, who is widely predicted to win the contest, has reportedly been secretly wooed by European politicians and officials in a bid to thrash out a new Brexit plan to avoid a no-deal exit, the Sunday Times reported.
It said figures from Ireland, France, Germany, Belgium and the Netherlands had established contact with the frontrunner's team and signalled their intention to do a deal.
Australian Associated Press