It is not the first time the actress has spoken out publicly on causes she supports. BBC News Online takes a look at the political episodes that have featured in her life.

Vanessa Redgrave, born in 1937, is a fully-fledged member of an acting dynasty.

Redgrave has enjoyed a long-lasting acting career

She is the daughter of actors Sir Michael Redgrave and Rachel Kempson, sister of Corin and Lynn Redgrave, and mother of Natasha and Joely Richardson.

She shared another passion with her father, that of politics, but has gone on to become far more involved in causes than he ever was.

Serious

These causes have often been controversial.

In 1977 during her acceptance speech at the Academy Award ceremony, she attacked "Zionist hoodlums" who had campaigned against her because she had defended the Palestinian Liberation Organisation.

The people I admire most are those who struggle for everyone ... to have their democratic rights (to say what they think)

Vanessa Redgrave, on BBC Radio 4's Woman's Hour

She has supported the exploited and oppressed, from Sarajevo to Tibet.

She is also a Unicef special representative and takes seriously her role to be at the service of children from any country.

More recently, she was among several actors who voiced their support for the return of the Elgin Marbles to Greece.

The Parthenon 2004 campaign pledged to make the British government and museum curators send back the ancient sculptures in time for the Olympics in Athens in 2004.

But Redgrave's left-wing politics have probably not helped her screen career, and some admirers have pointed out that most other actresses of her eminence have been made Dames.

Sense of justice

It is debatable whether her political forays have helped her career in Hollywood.

Others admire her strong sense of justice.

Mark Rylance, director of London's Globe Theatre, was moved to cast Redgrave in the male role of Prospero in Shakespeare's The Tempest (2000) because "Prospero is a man with immense power who is moved to mercy. Vanessa understands that".

Redgrave paid bail for the release of Ahmed Zakayev

In an interview with the BBC's Women's Hour in 1991, Redgrave herself admitted that sometimes her forays into political causes, coupled with her acting commitments had taken its toll on family life.

But she said: "As a mother you have got to have a view for now and a view for the future."

She added: "The people I admire most are those who struggle for everyone ... to have their democratic rights (to say what they think).