Linda Lovelace, pictured at Royal Ascot in the 1970s.

A version of the film was given an 18 certificate but it was heavily cut.

Now the BBFC has passed the whole 60 minutes uncut, following a rewriting in the adult video regulations, which was brought about by a landmark ruling in the High Court in May.

The BBFC changed its rules in July to allow sex videos to contain scenes of actual sex and more prolonged close up detail. Such films will be given R18 certificate, meaning they are only available in licensed sex shops.

Porn companies are now looking again at their back catalogues to see which previously banned films they could re-release in the UK.

Uncut'

Another notorious porn film, Debbie Does Dallas, has also been given an R18 certificate, allowing it to be shown uncut.

Years after making Deep Throat, its star Linda Lovelace said she had been forced to appear in it. She condemned the porn industry and claimed she had been forced to perform by her husband and manager.

Her books gave the anti-porn lobby powerful ammunition - that watching such movies was an act of violence against women.

But another porn legend, Marilyn Chambers, star of Behind The Green Door, told The Independent newspaper last year: "I feel sorry for those people who are miserable, like Lovelace.

"She wasn't forced. I was married to her husband for 10 years and he never forced me to do a goshdarn thing."

The Guardian's film critic, Derek Malcolm, told BBC News Online: "Linda Lovelace objected to the way her career was handled, but there are no rape scenes in the film.

'No great artistic merit'

"In fact, unless you enjoy watching fellatio, it's really rather boring."

He said: "It certainly doesn't have the artistic merit of The Devil And Miss Jones or Behind The Green Door, which were held up by the feminist movement as proof that women had their own sexual fantasies."

But Mr Malcolm said while Deep Throat was not a great film he welcomed the relaxation of censorship guidelines which allowed it to be shown uncut.

"People fear some sort of explosion but when they did this in Denmark and Sweden sales of porn films initially went up but then went right down."