British former Conservative Party leader Iain Duncan Smith arrives at Downing Street in London, Britain January 28, 2019. REUTERS/Hannah McKay

LONDON (Reuters) - Some of Prime Minister Theresa May’s senior ministers have undermined Britain’s Brexit negotiations by publicly warning they could vote to delay Brexit to avoid a no-deal exit, Conservative lawmaker Iain Duncan Smith said.

Business minister Greg Clark, work and pensions minister Amber Rudd, and justice minister David Gauke signalled in a Daily Mail column that they will side with rebels and opposition parties to stop a no-deal exit.

When asked about the move, Duncan Smith, a former Conservative leader, said he felt the public threat was a breach of cabinet collective responsibility.

“To do it publicly I think is a mistake on their part,” he told Sky News. “They are doing the prime minister no good at all and they do government no good at all by becoming quite so publicly opposed to what is essentially government policy.”

“Let’s let those going to do the negotiations negotiate and I would say to one or two of my colleagues in government: not a good idea to undermine them,” Duncan Smith said.