Dame Emma Thompson joined climate protesters in London on Thursday to declare that she wants to be among those demonstrators arrested by police.

However, it has emerged that the Oscar winning British actress was photographed a day earlier arriving at Heathrow Airport after apparently flying from Los Angeles where it is believed she had been celebrating her 60th birthday.

The Extinction Rebellion group, which is calling for flights to be used only in emergencies, insisted that any flight she had taken was an “unfortunate cost in our bigger battle to save the planet”.

It is estimated that a single 5,456-mile transatlantic flight between Los Angeles and London Heathrow would run up a three tonne carbon footprint. On Thursday, her London agent failed to say whether she took part in any carbon offsetting schemes - such as planting trees.

Dame Emma, who lives in Hampstead, north London, wore dungarees, looked tanned as she made victory V symbols with both hands while being filmed at the protesters’ base in Marble Arch.

The multi-millionaire star of films including Much Ado About Nothing and Sense and Sensibility said she had been unable to join the start of the “direct action” campaign on Monday because she had been celebrating her birthday with husband and fellow actor, Greg Wise. She did not reveal the location of her celebrations.