Sir Tom Stoppard will host a gala tonight in support of a theatre company banned in its home country.

Harold Pinter is also due at the event at Soho Theatre, where The Belarus Free Theatre are performing a double bill this week.

Belarus, which neighbours Russia, has come under international criticism for restricting freedom of expression, and its president, Alexander Lukashenko, is seen by the European Union as a dictator.

Belarus Free Theatre is known for staging covert, uncensored performances in its homeland, where only state-approved shows are allowed. It often puts on events in private houses and secret venues, texting details to spectators at short notice.

Sir Tom said he first saw the company in Belarus's capital, Minsk, three years ago. "They turned out to be a tiny bunch of outlaws, really up against it," he said. "Their life is one of persecution, arrest, short-term incarceration. Belarus is a one-off in Europe. It's a dictatorship without an ideology."

Sir Tom's West End hit Rock'n'Roll is about dissidents, under the former communist regime of Czechoslovakia.

Also attending tonight's gala will be actors Kim Cattrall, Maureen Lipman, Richard Wilson, Henry Goodman and Diana Quick.

Belarus Free Theatre will perform two plays, in Russian with surtitles. Being Harold Pinter combines transcripts from political prisoners with excerpts from Pinter's plays and his speech to the Nobel Prize Committee.

Generation Jeans is a political satire that looks at symbols of freedom in the theatre group's homeland, and the role denim plays.

The event is backed by writers' organisation Pen,which campaigns for freedom of expression. Jonathan Heawood, director of English Pen, said it would show Mr Lukashenko the world was watching his regime.

Soho Theatre artistic director Lisa Goldman said the venue in Dean Street wanted to support a kindred company. The gala is sold out but performances run until Saturday.