Britain's air travel nightmare worsened on Sunday as the Civil Aviation Authority extended its no-fly zone south to include airports in Birmingham and Norwich.

London's main airports remained open but an ash cloud from an Icelandic volcano mean restrictions are now in place over the Midlands, northern England, Scotland, Wales and Northern Ireland.

The restrictions will remain in place until at least 1am on Monday, air traffic authority Nats said.

A statement on the Nats website said: "For the period 1900 today (local time) until 0100 tomorrow (Monday) London's main airports will still be clear of the no-fly zone imposed by the CAA due to the high density volcanic ash cloud.

"The ash cloud continues to change shape and move further south to just north of Oxford during this period.

"This brings Birmingham and Norwich inside the no-fly zone in addition to those airports already affected.

"The northerly extent of the no-fly zone in England now includes Teesside, stopping just short of Newcastle, and tracking north west in a line just north of Carlisle, which remains in the no-fly zone.

"Airports inside the no-fly zone in England and Wales now include Teesside, Humberside, Leeds Bradford, Blackpool, Ronaldsway, Caernarfon, Liverpool, Manchester, Sheffield, Doncaster, Norwich, Birmingham and East Midlands.

"In Scotland the no-fly zone includes the Western Isles, Campbeltown, Prestwick and Oban.

"All airports in Northern Ireland remain inside the no-fly zone during this period."