Britain could join the United States and take military action against the Syrian regime if it is asked to do so, the Boris Johnson has suggested.

The Foreign Secretary said it would be "very difficult to say no" if Donald Trump's administration asks the UK for help in tackling Bashar Assad's regime in response to another chemical attack.

He said the Government may bypass a House of Commons vote to authorise it.

Earlier this month, dozens of people were killed in a sarin gas attack on a rebel-held area in Idlib province.

The US launched a cruise missile strike on a Syrian regime air base as a direct response to the attack.

Mr Johnson told BBC Radio 4's Today programme: "If [the US] come to us and ask for our support, whether it's with submarine-based cruise missiles in the Med... in my view, and I know it's also the view of the prime minister, it would be difficult for us to say 'no'."

Asked if MPs would have to approve Britain joining any action in the future, he said: "I think that needs to be tested."