PLANS for a new £2 billion international airport in Newport, were today being formally submitted to the government.

The Severnside airport plan, serving Wales and the west of England, proposes an airport with runways on a manmade island in the Severn Estuary.

If agreed, it could open by 2012, handle 30 million passengers a year by 2030 and help create 13,000 jobs.

But the airport's backers face a tough fight to get their scheme accepted - the government said last summer that Severnside was only likely if Bristol or Cardiff airports closed.

A final decision on just which airport schemes for the UK are approved will be made by the government in an aviation White Paper later this year.

Severnside's chairman Michael Stephen said the government had shown "a fundamental misunderstanding" of the Severnside proposal when it dismissed it "in one paragraph" of the aviation expansion consultation document, issued in July 2002. They are quite right that Cardiff and Bristol airports can handle the local demand, but neither of them are well located and neither can connect directly with a motorway or mainline railway," Mr Stephen said.

"Severnside will not, repeat not, be a regional airport. It will be an intercontinental airport, doing for southern and western England and South Wales what Manchester airport does for northern England and North Wales. "As the area in the UK with the greatest number of people wishing to fly is spreading out westward from London, we believe it makes sense to locate a major airport at the western end of the M4 corridor, and that it makes no sense to locate it anywhere to the east of London.

"Severnside's catchment area is enormous. It will stretch from Bournemouth and Plymouth in the south, from Cardiff and Bristol in the west and northwards from Swindon to Oxford, Coventry and Birmingham."

The submitted report says there would be huge savings on aviation fuel because transatlantic jets will not need to fly the 260-mile round trip to Heathrow if Severn-side went ahead.

Also, because Severnside would have uncongested airspace, aircraft would not need to stack in the air on arrival or burn fuel on the ground awaiting departure.

There would also be savings of road fuel because at present 65% of passengers from Wales and the West have to travel to Heathrow or Gatwick airports.

Road access to Severnside would be from the M4, M5 and M48 via short dedicated spurs to the terminal. Rail access would be via the airport's own mainline station directly alongside the terminal.

The Welsh branch of Friends of the Earth have opposed the plan but Severnside claim the environmental issues can be overcome.