Two leading human rights campaigners from Pakistani-occupied Balochistan are awaiting trial in London on charges of inciting others to commit an act of terrorism abroad.

Hyrbyair Marri and Faiz Baluch were arrested last December, just months after the then president of Pakistan, Pervez Musharraf, demanded that the British government arrest Baloch activists in London. In exchange, Musharraf is said to have offered to surrender Rashid Rauf to the British police. Rauf was wanted in this country in connection with the 2006 Islamist plot to blow up transatlantic airliners, which resulted in the conviction of three men on Monday. However, he mysteriously escaped from police custody in Pakistan days later.

Prior to Marri's arrest in London, Musharraf's regime had made repeated representations to the UK government to hand him over. When Musharraf met Gordon Brown in January this year, he held a press conference for Pakistani journalists in which he allegedly denounced Marri as a terrorist and praised the British authorities for co-operating with his regime.

The arrest of Marri - who fled to Britain in 2000, fearing for his life - and Baluch took place two weeks after Pakistani forces killed Marri's brother, Balach Marri, a prominent Baloch nationalist leader.

Both men were known for their peaceful, lawful campaigns to expose Pakistan's military occupation of Balochistan. The acting interior minister of the new democratically elected government of Pakistan, Rehman Malik, recently announced that all charges against Marri have been dropped and that the case against him had been politically motivated.

Despite these developments in Pakistan, the UK authorities are proceeding with the trial of Marri and his co-accused. There are fears that some of the prosecution evidence may have been provided by the shadowy Pakistani intelligence agency, the ISI.

Marri comes from a distinguished Baloch family and is an unlikely terrorist. A former Balochistan MP, his uncle is the UN Special Representative to Sudan, and his wife is descended from the first prime minister of Iraq. His brother Mehran Baluch, also exiled in London, is the Baloch representative to the UN Human Rights Council. He was the subject of an attempted extradition last year.

The arrest of Marri together with the murder of one brother and the attempted extradition of another, looks like a systematic attempt to target his family and crush three prominent voices of Baloch dissent.

A former British Protectorate, Balochistan gained independence in 1947, but was forcibly annexed by Pakistan in 1948 and has been occupied ever since. In recent years, largely as a result of Pakistani army attacks, 3,000 Baloch people have died, 200,000 been displaced and 4,000 arrested, often without charge, according to the Asian Human Rights Commission.