I was converted to the Tibetan cause when I heard the Dalai Lama speak in London in the 1980s. His modesty, reasonableness and obvious moral integrity made a profound impression.
My views were further formed when I visited a Tibetan refugee reception centre in Nepal in 2003 and met refugees who had just crossed the Himalayas to escape from Chinese-ruled Tibet.
They were emaciated, desperate, frostbitten and so traumatised that I was told my Chinese companion could not visit the centre with me, as the sight of any Chinese face would severely upset them.
Those traumatised refugees are people China claims the right to rule for ever, based on periodic conquests of Tibet, of which the most recent were in the 18th century and in 1949. Between those two conquests, Tibet was effectively independent. It was ironic and tragic that Tibet lost its independence just as many of the world's peoples were regaining theirs, after decades or centuries of European colonialism.
The United Nations International Covenant on Civil and Political Rights states: 'All peoples have the right of self-determination.'
The academic consensus today is that this statement refers to liberating the peoples of Africa and Asia from European colonialism, and that it therefore does not mean that people who live in one part of any country can decide to leave to set up their own separate country.