Ralph Fiennes and Rachel Weisz co-star in The Constant Gardener

The author, stars Ralph Fiennes and Rachel Weisz and director Fernando Meirelles were all at the event.

More than 180 films from 50 countries are presented at this year's event, which runs until 3 November.

Gwyneth Paltrow, Susan Sarandon and Kirsten Dunst are among the other actors scheduled to attend.

The festival ends with the British premiere of Good Night and Good Luck, actor George Clooney's second film as director.

World cinema

Organisers said they could not confirm whether the former ER actor would be present at the screening but were hopeful he would attend.

Now in its 49th year, the London Film Festival is described as "the single most concentrated annual focus on new world cinema in Britain".

George Clooney (l) directs and stars in Good Night and Good Luck

Events take place in 13 cinemas across the city and encompass screenings, discussions and celebrity appearances.

Director Terry Gilliam, screenwriter Shane Black and Mexican actor Gael Garcia Bernal will take part in screen talks at the National Film Theatre.

The line-up also includes an extensive programme of shorts, documentaries and restorations.

"We are delighted with the quality and strength of this year's selection," said artistic director Sandra Hebron.

Unlike Cannes, Venice and other leading cinema festivals, London is not a competitive event.

'Celebration'

But Hebron denies this prevents organisers attracting big names to the two-week showcase.

"Not having a competitive section is very appealing to film-makers - they're not put into competition against each other, making it more of a celebration of a broad spread of creativity.

Joaquin Phoenix plays the late Johnny Cash in Walk the Line

"The festival does give some prizes; it's just that we choose to concentrate on new talent and first- and second-time film-makers."

While London does not have its version of Berlin's Golden Bear or Venice's Golden Lion, Hebron says its proximity to the Oscars and Bafta Awards works in its favour.

"It's fortunate we coincide with the beginning of the awards season," she told the BBC News website.

"That has become very important in terms of the calibre of films and guests we attract."

Several potential Oscar contenders are included in the line-up, among them Walk the Line - with Joaquin Phoenix as the late singer Johnny Cash - and Paltrow's drama Proof.