The Iranian dissident film-maker Jafar Panahi won the Golden Bear at the Berlin film festival for his Tehran road movie Taxi in what critics described as a victory for freedom of speech and the art of cinematic storytelling.

Panahi, who is banned from making films by the Iranian authorities and forbidden from travelling abroad, stars in his own film as a taxi driver talking to his passengers as he drives them through the streets of Tehran.

The decision to celebrate Panahi, who has been described as the “Iranian Woody Allen”, cements the Berlinale’s status as the most politically driven of the world’s main film festivals. “Instead of allowing his spirit to be crushed and giving up, instead of allowing himself to be filled with anger and frustration, Jafar Panahi created a love letter to cinema,” said Darren Aronofsky, the American director and Berlinale jury president. “His film is filled with love for his art, his community, his country and his audience.”

Panahi’s award was picked up by one of the film’s young female stars, who broke down on stage saying she was “too moved” to talk. She was comforted by the French actress and jury member Audrey Tatou.

The award ceremony of the 65th Berlinale, which was replete with stars including Cate Blanchett, Juliette Binoche, Christian Bale and James Franco, was also a huge success for British cinema – Tom Courtenay and Charlotte Rampling won the best actor and actress awards for their leading roles in 45 Years, a much-feted drama directed by the rising star Andrew Haigh in which a long-term marriage breaks down within a week.

Set in the flat and drained landscape of the Norfolk broads, the film competed with far more glamorous pictures, such as Werner Herzog’s biopic of the British explorer and Arab expert Gertrude Bell, starring Nicole Kidman, and Everything Will Be Fine, Wim Wenders’s 3D portrait of guilt and forgiveness starring James Franco and Charlotte Gainsbourg. But critics were bowled over by Haigh’s slow-burn drama, with both stars winning praise for their mix of British understatement and subtle eroticism.

Accepting the award, Rampling, 69, joked that by receiving the Silver Bear she was like the ambitious daughter “taking the baton” from her father, Godfrey, a British colonel who won a gold medal at the 1936 Berlin Olympics for the 4 x 400 metres relay. “I think this bear has done the trick,” she said.

Courtenay, 77, said he had waited for 30 years to receive a Berlinale bear, following “my friend Albert Finney who won in 1985”. Rampling revealed that one of the most challenging aspects of the film had been Courtenay’s inability to dance, which Courtenay said had meant repeated takes of a key dance scene. “We did 20-odd takes,” he said. “But my eyes moistened in every single one so we must have done something right.”

In a further boost to British film interests, Kenneth Branagh was among the stars on the red carpet following the world premiere last Friday of his live-action modern retake of Cinderella for Disney, as well as Peter Greenaway, the British director whose ambitious and sexually explicit biopic of the Russian director Sergei Eisenstein, Eisenstein in Guanajuato, was warmly received.

Other awards included the Grand Jury prize, or the Silver Bear, for the Chilean director Pablo Larrain for El Club, a film that centres on a group of Roman Catholic priests who have in various ways dishonoured the church and have been relocated to a small seaside town. The jury said it expected the film would become a “classic of the history of cinema”.

In an unusual move, the Romanian and Polish directors Radu Jude and Malgorzata Szumowska were both given best director honours for their films Aferim! and Body. The Guatemalan film Ixcanul Volcano by director Jayro Bustamente – which tells the story of a poor Mayan teenager on a coffee plantation who plots to leave for the United States with her boyfriend – secured a Silver Bear “for a feature that opens new perspectives”.

Some critics expressed relief that the award ceremony, with its focus on the more political and often lower budget films, had finally steered the attention away from the film adaptation of the S&M novel Fifty Shades of Grey, which had its international premiere at the festival earlier in the week and while not in competition, looked to have stolen the limelight despite the widespread opinion that it did not deserve a place at a festival better known for its social realism rather than product-placement-driven soft-porn melodrama.