Mobile phone calls will be allowed on planes flying in European airspace under new European Commission rules. The decision means that mobiles could be used once a plane has reached an altitude of 3,000m or more.

It follows six months of consultation by the European regulator and the first services could launch next month.

Viviane Reding, the EU telecoms commissioner, has warned operators to keep the cost of calls made on planes at a reasonable level.

"If consumers receive shock phone bills, the service will not take-off.

"I also call on airlines and operators to create the right conditions on board aircraft to ensure that those who want to use in-flight communication services do not disturb other passengers," she said.

The European Commission has introduced new rules to harmonise the technical requirements for the safe in-flight use of mobile phones.

The commission is also making it possible to enable the national licences granted to individual airlines by a member state to be recognised throughout the EU.

The decision to offer the services now falls to individual airlines. However, there are other regulatory hurdles to overcome before the technology is considered to be fully approved.

The European Aviation Safety Agency still needs to approve any hardware that would be installed in aircraft to ensure that it did not interfere with other flight systems.

How does the system work?

Plane Phone

The plan is to install small mobile phone base stations, called pico cells, in aircraft that will be switched on after take-off. The base station generates a bubble of coverage in and around the aircraft.

Calls made via the pico cell will be routed to terrestrial networks via satellite link. Across Europe radio spectrum has been set aside for the technology.

The services could stop working once aircraft leave European airspace.

Martin Selmayr, spokesman for Ms Reding's office, said that flight captains would be able to switch off the on-board service if they felt it necessary.

Initially, only second generation networks will be offered but growing interest would mean that third generation, or 3G, services will follow.

The first flights offering calls could start as early as next month.

Air France is believed to be ready to deploy the technology while Ryanair is expected to submit an application.

The cost of making a mobile phone call from a plane will be higher than making one from the ground.

In the UK, regulator Ofcom said it would investigate and address any evidence of "excessive charges and abuses of competition" if prices were set unfairly by airlines and mobile networks.

Ms Redding has said the EC had no plans to cap the cost of calls made on planes.

The European Commission backing means planes registered in one country would be able to offer mobile communications services to passengers when flying over other EU countries without having to apply for additional national licences.