Ian Livingstone, president of Eidos, said Lara Croft's latest adventure includes "gritty realism"

The makers of the new Tomb Raider computer game have insisted there were "no outside pressures" to include more violence after it became the first in the series to receive an 18 rating.

Ian Livingstone, life president of Eidos, said Lara Croft's latest adventure features combat play with "gritty realism" as she is left stranded on a mysterious island in her first outing in three years.

But Mr Livingstone, who received a CBE in the New Year's Honours List, denied the success of shooter games such as Call Of Duty and Grand Theft Auto had influenced the game's developers to include more fighting scenes.

"There was no outside pressure to change," he said.

"Audiences today want realism in their games. The pillars of Tomb Raider are exploration and adventure, puzzle-solving and combat.

"Combat had always been an after-thought in previous Tomb Raiders so we though we want to raise the combat.

"To make that realistic she's going to have to sustain damage. Previously she'd been armour plated, Teflon covered and adventurous.

"A decision was made to make it 18 because of the combat involved, the graphics involved and that gritty realism. It's definitely the correct decision."

The first Tomb Raider game for Playstation consoles was released in 1996 but its central character character began life very differently.

Core Design had created a male character called Rick Dangerous before the popularity of "girl power" in the mid-1990s influenced developers to change the gender of their protagonist, Mr Livingstone said.

After initially calling her Lara Cruz, the game's makers decided to look through a telephone book to decide on her surname.

"Everyone thought, fantastic idea but don't like the name," Mr Livingstone added.

"Somebody went through a phone book and came up with the name Croft because that had the quintessential English surname."

Mr Livingstone, 63, who wrote the successful Fighting Fantasy book series, has recently led a campaign for computer science to be included in the national curriculum.

He added: "Ed Vaizey, the culture minister, has been very supportive and we've managed to convince (Education Secretary) Michael Gove that computer science will be a major part of the new ICT curriculum, which is going to be now called computing.

"We've got to turn our nation of digital users into a nation of digital makers."

Tomb Raider for PC, PS3 and Xbox 360 is released on Tuesday.