Flights will finally start again in the UK tomorrow after air traffic control company Nats lifted restrictions for Scotland and part of northern England.

After days without any flights above the UK due to volcanic ash, Nats said tonight that Scottish airspace would open at 7am tomorrow.

Airspace south to a line between Teesside and Blackpool will also be open, with the hope that restrictions over the rest of England and Wales will be lifted later tomorrow, Nats said.

But current restrictions for the UK would carry on until 7am tomorrow.

Nats said: "The volcanic eruption has reduced and the volcano is not currently emitting ash to altitudes that will affect the UK. Assuming there are no further significant ash emissions, we are now looking at a continuously improving situation.

"This is a dynamic and changing situation and is therefore difficult to forecast beyond 7am tomorrow.

"However, the latest Met Office advice is that the contaminated area will continue to move south, with the possibility that restrictions to airspace above England and Wales, including the London area, may be lifted later tomorrow.

"It is now for airports and airlines to decide how best to utilise this opportunity. Passengers should contact their airlines to find out how this will affect their travel plans."

The news will come as an enormous relief to cash-strapped airlines and the estimated 150,000 Britons stranded abroad by the flights ban.

Before the Nats announcement, Prime Minister Gordon Brown said that two Royal Navy ships were to be used to help bring Britons home, with a third vessel also possibly being deployed.

The go-ahead for flights came as airlines pointed to successful test flights through closed airspace as a reason for lifting restrictions.

Airline Flybe said it would start operating services again from Aberdeen, Belfast City, Edinburgh, Glasgow, Inverness and Newcastle airports from 10.05am tomorrow.

The first flight will take off from Belfast City airport at 10.05 heading for Edinburgh.

The lessening of the impact of the volcano and the promise of a change in wind direction by the end of the week holds out the hope that the crisis can soon be resolved.

The cost to airlines and other affected industries is immense and British Airways said today that European carriers had asked the EU and national governments for financial compensation.

BA, which took a test flight through a successful run out across the Atlantic yesterday, said the flight restrictions had cost it between £15 million and £20 million a day.

While Mr Brown and Transport Secretary Lord Adonis outlined measures to get Britons home, holiday companies Thomson and First Choice said they were laying on coaches to repatriate around 5,000 stranded tourists in the Spanish resorts of Alicante and Malaga.

Thomas Cook also announced that it was flying holidaymakers from the Caribbean to Portugal and getting them home from there.

Mr Brown said HMS Ark Royal and HMS Ocean would be used to help stranded Britons. A third vessel, HMS Albion, which was on its way to Spain to pick up troops, "may be able to be of help", the Prime Minister said.

The International Air Transport Association was highly critical of the European response to the ash crisis which, it estimated, is costing the aviation industry around 200 million dollars (£130 million) a day.

Meanwhile, ferry companies and train operators have been enjoying a travel boom in the absence of any UK plane travel.

Channel Tunnel high-speed train company Eurostar said it was putting on extra trains every day this week.