US military aircraft leave second UK base

At least 10 US Air Force refuelling aircraft left a second airbase in Britain on Monday.

Flight tracking data seen by BBC Verify shows the aircraft left RAF Mildenhall in Suffolk and landed at other American bases in Europe and also at Prestwick Airport in Ayrshire.

The Wall Street Journal reported that this was in response to a threat from Iran but the BBC has not independently verified that claim.

Monday's departures come weeks after the US withdrew its bombers from RAF Fairford airbase over a suspected Iran-linked security incident.

Asked about Monday's flights, an MoD spokesperson told the BBC: "We do not routinely comment on the activity of other nations. Aircraft and other assets move regularly ​according to operational ​requirements."

Using public tracking site Flightradar24 BBC Verify has been able to see USAF KC-135 tankers leaving Mildenhall throughout Monday.

Two aircraft that left initially flew to US bases in Germany and Italy. The first KC-135 then returned to Mildenhall before heading east and landing at Spangdahlem airbase in Germany. The other aircraft - having flown circuits over Aviano airbase in Italy - flew on to and landed at Spangdahlem.

Flight-tracking data also shows eight other US KC-135s left Mildenhall later on Monday.

An aircraft that landed at Prestwick in Scotland on Monday is with the Nebraska Air National Guard, meaning it may have been on a regular stop before heading back to its American base.

Downing Street has insisted that UK airbases are safe following this decision by the US to move some military aircraft to locations in Europe.

The prime minister's official spokesperson said "the protection of our bases, both in the UK and across the world, is a top priority, we work closely with the police and our allies to protect our sites".