They then set off distress signals releasing clouds of smoke which drifted across the rough moorland.

Similar action was taking place on the tops of more than 100 mountains, hills and skyscrapers around the world - a symbolic international protest and statement of opposition to China's occupation of Tibet, said one of the organisers, Jodie Underhill.

The Yorkshire protest took place at Stoodley Pike, the site of a peace monument, built to mark the end of the Crimean War (an earlier, storm-destroyed Pike had been built to mark the end of the Napoleonic Wars) and was seen for miles around, she said.

The protest was organised by Calder Valley support group Love 4 Tibet, whose main aim is to raise funds for the Tibetan Children's Village in northern India.

The group sponsor two children at the TCV which cares for destitute refugee Tibetan children.

The founders of the group are Jodie and Richard Dalby. This week they switched their fund-raising work into peaceful protest.

Ms Underhill, 32, a hospice worker from Cornholme, and Mr Dalby, 40, a musician from Walsden, together with Ms Nightingale, a drug rehabilitation worker from Todmorden, and accompanied by other Tibet supporters walked released the flares at 1pm on Friday.

"The Olympic games are Tibet's biggest chance to focus world attention on what is happening in Tibet, and to campaign for an end to the occupation," explained Ms Underhill.

"Once the games are over attention will be switched elsewhere.

"We have to keep up the pressure. Around a thousand people in Tibet are still unaccounted for since the protests in March and no children have managed to escape Tibet since then. This is a matter of grave concern."

Mr Dalby, who with Ms Underhill has raised thousands of pounds for Tibetan causes ranging from sponsoring children to training midwives, said: "The games have brought a growing awareness of what is happening in Tibet.

"Just possessing a Tibetan flag is punishable by imprisonment - and so is displaying a photograph of the Tibetans' spiritual leader, the Dalai Lama."

The previous night, on Thursday, August 7, around 100 supporters gathered in Hebden Bridge square for a candlelit vigil.

The vigil held on the eve of the Olympic Games was part of a worldwide campaign to raise awareness of the situation in Tibet.

And on the Pennine hilltop, the Tibetan flag will remain there for the duration of the Olympic Games, added Miss Underhill.