Triggerstreet.com aims to give new writers and film-makers constructive criticism about their ideas.

Spacey used a press conference in London on Tuesday to launch the site in the UK.

"If you have done well in whatever business you are in, it is your duty to send the elevator back down and try to help bring up the next generation of undiscovered talent," Spacey said.

"When I needed help in starting my own career, many people gave me encouragement and became my mentors. Now I want to try to do something inspiring and interactive for new talent and for the film-making community."

Martin Scorsese has given exclusive footage to the site

Users will be able to upload their work on to the site, but only after they have reviewed two other scripts on the database.

Organisers say this will create a proper online forum for scriptwriters.

Experienced scriptwriters are also being asked to review scripts on the site.

The Usual Suspects star says it is important to get the industry's veterans to help newcomers.

Triggerstreet also wants film-makers to upload their finished short films, which can be reviewed on the site.

Three times a year the site will host its own online film festival .

The films will be judged by a panel including Sean Penn, Ed Norton, Mike Myers, Billy Crystal, Cameron Crowe, Danny DeVito, Tim Burton and U2 singer Bono.

Ranch

There will also be exclusive footage from famous directors, including Martin Scorsese, Robert Zemeckis, Bill Paxton and Ted Demme, made before they became established.

Triggerstreet.com president Dana Burnetti said: "We are using the Internet for the purpose for which it was created - as a tool to communicate.

"No longer will you need to 'know' somebody to get a foot in the Hollywood door."

Triggerstreet is the name of Spacey's production company - the title comes from a street in the San Fernando Valley where the actor grew up.

It bordered a ranch owned by cowboy star Roy Rogers, and was named after his horse.