Titanic contained no sexual chemistry and that's official.

Scientists have discovered what they believe is the formula for creating sexual chemistry on the big screen.

The academic experts boiled down sexual chemistry into its essential elements after watching a selection of romantic films.

Romantic comedy When Harry Met Sally topped their list, with a top rating of 10 out of 10 on the scale of movies with sexual chemistry.

Casablanca came second – scoring 9.5 – for the electric relationship between the characters played by Ingrid Bergman and Humphrey Bogart.

Films like Breakfast at Tiffany’s (9) and Pretty Woman (7) also scored well, but the likes of Hugh Grant and Sandra Bullock’s Two Weeks Notice received just two out of 10.

The newest film in the study, Lost in Translation, scored nine for “the subtle relationship” portrayed by Scarlett Johansson and Bill Murray.

Despite Titanic winning several Oscars, Kate Winslet and Leonardo DiCaprio were given a dismal zero, while Ghost, starring Demi Moore and Patrick Swayze, scored seven.

Psychiatrist Stephanie Charters, at King’s College London, found that voice, eye contact, body language and excitement, which she termed VIBE, should be used to measure sexual chemistry.

For voice, the researchers, who were asked to carry out the task for Sky Movies, looked out for tone and flutter, saying “it takes more than a well-delivered line” to add to the sense of romance.

Ms Charters said: “In Titanic, the way they speak to each other isn’t natural. It just doesn’t come across as genuine.

“In Ghost, Patrick Swayze’s desperate and sad lines as he tries to communicate to his wife shows perfect use of voice.”

The researchers looked at how actors use their eyes to convey sexual attraction.

She said: “When Meg Ryan’s character Sally shows that it’s easy to fake an orgasm by giving a demonstration in a restaurant, you can see Billy Crystal’s character Harry look at her in a different way.

“For the first time, he looks at her with different eyes and the floodgates open.”

Experts say Dirty Dancing contains the perfect example of body language, with the sexual tension between Patrick Swayze and Jennifer Grey hotting up on the dancefloor, while the sex scene in a steamed-up car on the boat in Titanic lacks excitement.

Experts also looked for the sense of excitement and anticipation conveyed while falling in love.

“When Harry finally confesses to Sally he is in love with her no one can help but feel a slight butterfly in their tummy,” Ms Charters said.

“In Titanic, there isn’t any of that, they confess their love for each other pretty quickly.”

The research was carried out to mark Sky Movies Romantic Long Weekend, which starts on Friday.

Here is the list of movies ranked according to sexual chemistry:

10 When Harry Met Sally (1989) (Meg Ryan/Billy Crystal)

9.5 Casablanca (1942) (Ingrid Bergman/Humphrey Bogart)

9 Breakfast at Tiffany’s (1961) (Audrey Hepburn/George Peppard)

9 Lost in Translation (2003) (Scarlett Johansson/Bill Murray)

7 Pretty Woman (1990) (Julia Roberts/Richard Gere)

7 Ghost (1990) (Demi Moore/Patrick Swayze)

5 Dirty Dancing (1987) (Jennifer Grey/Patrick Swayze)

3 My Big Fat Greek Wedding (2002) (Nia Vardalos/John Corbett)

2 Two Weeks Notice (2002) (Sandra Bullock/Hugh Grant)

0 Titanic (1997) (Kate Winslet/Leonardo DiCaprio)

(Irish Examiner, Dec 15th 2004)