Gordon Brown has said that airports are "taking advantage of the window of opportunity" as the impact of the volcano ash cloud temporarily lessened.

The Prime Minister has also insisted passenger safety would remain "paramount" though.

The PM said the effects from the Icelandic volcano were expected to strengthen again, but experts were looking at opening sections of airspace where it became available.

He also stressed that the Government was putting in place arrangements to bring stranded Britons home if they could reach ports on the other side of the Channel.

Speaking in 10 Downing Street, Mr Brown said: "We are taking advantage of the window of opportunity, but our first priority is that passengers will always be safe when they travel."

It comes as the first of three Royal Navy warships began rescuing Britons stranded by the air chaos today.

HMS Albion came alongside at Santander in northern Spain this morning and started loading about 250 troops and 200 civilians to take them back to the UK.

Flights before 7pm today will only be allowed in eastern Scotland and part of northern England, air traffic control company Nats said.