Titanic director James Cameron has apologised for an historical inaccuracy in his blockbusting movie.

On his first visit to Southampton, where the ill-fated liner sailed from, the film-maker said: "I've come to the realisation that it was probably a mistake to portray a specific person, in this case First Officer Murdoch, as one who fired a weapon.

"That was probably a mistake because he has some family left. They took exception to that and rightly so."

Cameron's Oscar-winning film hit controversy over its portrayal of Chief Officer William Murdoch as a murderer and bribe taker, which proved expensive after family and friends objected saying he was, in fact, a hero.

Film distributors Twentieth Century Fox were forced to give $8,000 to a fund commemorating him after the film showed the first mate killing two passengers trying to get on a lifeboat, before killing himself.

Cameron has promised to return to Southampton after visiting the city yesterday to accept an honorary degree. He was so impressed with Southampton University's Oceanography Centre he pledged to come back for a longer look.

Canadian-born Cameron, 49, was shown around the aquarium and talked to researchers about the latest deep-sea underwater film device.

"Hopefully, I will run across some of them in the world of underwater exploration in the future. It's a very small community involved in this field."

Cameron, who also directed Aliens, Terminator 2 and True Lies, was given the prestigious honour for his "outstanding contribution" to marine science and maritime archaeology in his film-making.

His 1997 blockbuster Titanic featured real footage of the wreck of the ill-fated Southampton liner lying on the Atlantic seabed.

He has also directed a three-dimensional film called Ghosts of the Abyss, including previously unseen footage of the wreck.

Cameron flew into the UK on Monday night in order to attend yesterday's graduation ceremony at the university's Turner Sims concert hall in Highfield.

He said: "As this was the home port of Titanic the day has extra resonance. Together, the Oceanography Centre and Southampton's history make this a very special event for me."

Mr Cameron, who was due to fly home this morning, also found time to visit the city's Titanic museum.

His next film, Aliens of the Deep, is due to be released in the US next January.

He is also involved in the pre-production of a big science fiction three-dimensional film but refused to reveal any more details.