An artist's impression of the Fife to Edinburgh hovercraft service

The service will carry up to 130 passengers at a time between Portobello in Edinburgh and Kirkcaldy in Fife.

If successful, it is hoped it will cut congestion for commuters on the Forth road and rail bridges by carrying about 470,000 passengers a year.

Bus company Stagecoach is trialling the system between 16 and 28 July, with the backing of �100,000 of public funding.

The firm is to run 22 services a day during the two-week trial.

The 28 metre (92ft) hovercraft, which can travel at about 35 knots, will cost passengers �4.50 for a return journey.

Stagecoach had planned to launch a test service on the route in October last year but delays in getting environmental approval from Scottish Natural Heritage (SNH) forced them to put the trial back until this summer.

Bird life

Brian Souter, Stagecoach Group chief executive, said the service would have numerous public benefits.

He said: "The Forth estuary is an under-used resource and we are looking forward to giving people a chance to see the benefits this technology could bring to the region's communities, economy and public transport system.

"It is crucial we have a wide range of public transport options to cope with the increasing flow of people between Fife and the Edinburgh area."

During the trial an ongoing environmental impact study will take place to determine the effects of the service, particularly in relation to bird life.

Stagecoach estimates that running a two-craft operation would cost about �2m a year.