Harold Pinter, the British playwright, said today that his longstanding political activism may have played a role in the decision to award him the 2005 Nobel Prize for Literature.

The 75-year-old, whose works include The Birthday Party, The Dumb Waiter and The Caretaker, was praised by the Nobel jury today for having "restored" the stage play as an art form.

But, appearing on the steps of his West London home this afternoon, Pinter acknowledged that he was known not just for his 29 plays but also for political activities and opposition to the war in Iraq.

"I’ve been writing plays for about 50 years," he said. "But I am also very politically engaged and I am not at all sure to what extent that factor had anything to do with this award."

His face cut and bruised after a recent fall and carrying a cane for support, Pinter added: "I think the world has had enough of my plays by now. But I think I shall certainly be writing more poetry and certainly remain deeply engaged in the question of political structures in this world."

The Nobel jury said that the playwright "uncovers the precipice under everyday prattle and forces entry into oppression’s closed rooms".

"Pinter restored theatre to its basic elements: an enclosed space and unpredictable dialogue where people are at the mercy of each other and pretence crumbles," the academy said.

His efforts in promoting human rights were also praised by the jury, which was rumoured to be split over the decision.

The award was greeted with acclaim from leading figures in British theatre. The playwright Sir Tom Stoppard said: "It’s wholly deserved and I’m completely thrilled. As a writer, Harold has been unswerving for 50 years."

The actor, writer and director Sir Alan Ayckbourn, who appeared in a production of The Caretaker directed by Pinter, said: "It couldn’t have happened to a nicer person and it’s a most fitting award."

The playwright David Hare said: "This is a brilliant choice. Not only has Harold Pinter written some of the outstanding plays of his time, he has also blown fresh air into the musty attic of conventional English literature, by insisting that everything he does has a public and political dimension."

The presentation of the award will take place on December 10, the anniversary of the death of Nobel prize founder Alfred Nobel.

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