As the industry increasingly looks to take advantage of back catalogues, the world's largest and most valuable film archive is now being made available at the click of a button - for free.

The Mediatheque room of the new BFI Southbank beneath London's Waterloo Bridge already has available 300 film and TV titles from the national archives, ranging from Brief Encounter to Monty Python. "We want people to come in and rifle through the archives to view films they might not have known even existed," says British Film Institute (BFI) president Amanda Nevill.

These films can also be watched in the new freestanding box cinema in the foyer. "There will be a great deal of flexibility about what you can watch (in the studio), but there's also a structured programme with seasons of work from directors such as Roberto Rossellini and Tim Burton," adds Nevill.

The complex, revamped and rebranded from the National Film Theatre to BFI Southbank, includes a gallery, bar and restaurant. The site relaunched on March 14 after a six-month delay, with a renovation budget of $12m (£6m) in National Lottery funding. The BFI has plans to increase the number of archived films available at the site, but Nevill accepts that preserving and transferring them to digital comes at a massive price.

"We worked out it would cost more than $2bn (£1bn) to digitise all the archives," she says. "Film is inherently unstable and can deteriorate within 10 years if not looked after properly. The preservation of each feature film can go from $200,000 (£100,000) up to $1.2m (£600,000) before it's ready."

As a result, Nevill accepts they will not be able to restore all 750,000 films in the BFI archives, but will look to raise their profile and hopefully increase funding. "The more people that want to see it, the more we can raise the bar about the fact the film archive needs massive investment. We need $20m-$30m (£10m-£15m) over the next two to three years to make it really safe."

Film director and BFI chairman Anthony Minghella told Screen International: "We've been custodians of this extraordinary treasure of the BFI film archive, but it's in Hampstead and not everyone can access it there. The Mediatheque idea is all about access and the plan is to roll it out across the UK."

But the archive will not be accessible online, due to rights issues and "the film industry wouldn't touch the films with a barge pole", says Mark Reid, acting head of education and learning at the BFI. Instead, Shaun Woodward, minister for creative industries and tourism, believes: "We need to work with the private sector to restore our old films and transfer them to DVD. We're sitting on a potential goldmine."

BFI SOUTHBANK STATISTICS

- BFI Southbank site cost $12m.
- Mediatheque has 14 bookable viewing stations.
- Some 300 film and TV titles are available.
- By end of 2007, more than 700 titles are expected to be available.
- The BFI is launching 'Beautiful South', a programme that works with up-and-coming film-makers from south London.