James Mattis, US defence chief, was in London on Friday

Gavin Williamson, the new defence secretary, risks angering America over plans to slash the British fleet of minehunter ships in the Gulf.

Admirals are considering removing two of the Royal Navy’s four minehunters that are permanently stationed in the Gulf, according to well-placed sources.

Britain’s minehunters are highly valued by America as a deterrent against Iran using mines to block the Strait of Hormuz, the world’s most important choke point for oil supplies. In late 2011 Iran threatened to close the strait in response to sanctions.

It comes as tensions are growing in the Middle East after America’s president, Donald Trump, refused to certify that Iran was complying with a nuclear deal struck in 2015.

The navy scrapped two of its 15 minehunters — HMS