Margaret Atwood has said that she is humbled to win an award from PEN celebrating her political activism, describing herself as “a stand-in for the thousands of people around the world who speak and act against [human rights] abuses”.

The PEN Pinter prize was set up seven years ago in memory of the Nobel prize-winning playwright Harold Pinter, and is given to a writer of outstanding literary merit who, in the words of Pinter himself on winning the Nobel, casts an “unflinching, unswerving” gaze upon the world and shows a “fierce intellectual determination ... to define the real truth of our lives and our societies”.

The Booker prize-winning Canadian author was picked by a judging panel chaired by Maureen Freely, who said: “In a profession dominated by careerists who are content to tend to their own gardens, Margaret Atwood is the shining exception.

“She does not just stand up for her principles: in novel after novel, she has put them to the test. What she does as a campaigner has only served to deepen her work as a writer of fiction. She is an inspiration to us all,” said Freely.

Antonia Fraser said her late husband ‘admired Margaret Atwood in three ways: as a writer, a campaigner and a person’. Photograph: Murdo Macleod/The Guardian

Atwood, who was praised by judges as an “exemplary public intellectual” and “consistent supporter of political causes” whose “work championing environmental concerns comes well within the scope of human rights”, said she knew Harold Pinter personally, and that she was humbled to win a prize in his name.

“I knew Harold Pinter and worked with him – he wrote the scenario for the film version of The Handmaid’s Tale, back in 1989 – and his burning sense of injustice at human rights abuses and the repression of artists was impressive even then,” said Atwood. “Any winner of such an award is a stand-in for the thousands of people around the world who speak and act against such abuses. I am honoured to be this year’s stand-in.”

Pinter’s widow, the writer Antonia Fraser, said that her late husband “admired Margaret Atwood in three ways: as a writer, a campaigner and a person”, and that “he would be especially delighted by her generous response to this award”. Fraser joined Freely on the judging panel for the award, alongside fellow judges Vicky Featherstone, Zia Haider Rahman and Peter Stothard.

Atwood will now choose a co-winner of the prize, the 2016 International Writer of Courage, who will be revealed at an event at the British Library in October. The winner, said PEN, would be an international writer “who is active in defence of freedom of expression, often at great risk to their own safety and liberty”, with previous recipients including Gomorrah author Roberto Saviano, Mexican journalist Lydia Cacho and the imprisoned Saudi blogger Raif Badawi.

Atwood will tour the UK in October and November for her latest book Hag-Seed, a re-telling of Shakespeare’s The Tempest. The nine-date tour will include a talk at the RSC Royal Shakespeare Theatre in Stratford upon Avon.