ANTON Balasingham provided the intellectual framework for the violence of the Liberation Tigers of Tamil Eelam. He was the brains behind the brawn, someone the leadership could turn to for ideological guidance, philosophical justification and political explanation while the killing went on.

A forlorn-faced man, ill with a transplanted kidney, he travelled to devastated northern Sri Lanka in 2002 to act as the rebels' negotiator in peace talks brokered by Norway. The Tigers vainly asked India to host the encounter so that Balasingham could be near a hospital in case of an emergency. Everybody feared that he would die before the best chance of peace in more than two decades could be seized. 

The difficulty was how to get him to Sri Lanka without his being assassinated. So, accompanied by his Australian wife, Adele, he flew in from London to the Maldives and transferred to a privately chartered De Havilland DHC-6 Twin Otter seaplane, which landed on a reservoir in a rebel-controlled area south of Kilinochchi. The Colombo Government had ordered the airspace above northeast Sri Lanka to be kept clear of all aircraft, and the seaplane maintained radio silence throughout its journey lest hostile forces picked up the signal, revealing its whereabouts and mission.

The First Secretary of the Norwegian Embassy in Colombo was aboard. Immediately after it landed a Sea Tiger craft moved in to provide security. On the shore, the plump figure of Velupillai Prabhakaran, leader of the Tigers, could be made out standing with his wife Mathivathany, and other Tigers leaders. They were awaiting "Bala Annai" and "Auntie", as young Tigers cadres called the Balasinghams. A house had been constructed for their stay.

This elaborate journey was a measure of the importance the Tigers placed in the one man they could trust with their destiny in what looked like being a breakthrough in talks with the Sri Lankan Government of Ranil Wickremesinghe. Everybody underestimated, however, the determination of hardcore Sinhalese organizations like the JVP and hardline Buddhist clergy to scuttle any deal that gave the Tamils even a hint of autonomy. The peace deal failed, and Balasingham had made a life-threatening journey with no more to show for it than the continuation of a shaky ceasefire.

Under his guidance the Tigers had entered several rounds of successful talks with the Government, all brokered by Norway, watched suspiciously from the sidelines by President Chandrika Kumaratunga. In the end she used her presidential powers to scupper the deal.

Her successor, President Mahinda Rajapakse, also rejected the concepts of a Tamil homeland and Tamil nationhood. The JVP, in a previous incarnation a fanatically violent organisation but by now the third biggest political party in the country, had threatened "undiplomatic" consequences if the peace deal went through. All of this, Balasingham said with uncharacteristic understatement, represented an obstacle.

In taking the Tigers to the brink of peace, Balasingham had steered the rebels away from their earlier demand for a fully fledged independent state called Eelam. What the Tamils wanted, he said, was "a homeland and self-determination". If that demand were rejected and the "oppression" continued, there would be no option but to fight for full statehood. Those words signalled the collapse of peace hopes.

Balasingham, who gained a PhD from South Bank Polytechnic in London (his dissertation was on the psychology of Marxism), had been the Tigers' theoretician since the early 1990s and clearly had the full confidence of Prabhakaran. He had a British passport and in 1999, much to the Sri Lanka Government's anger, was allowed to settle in London with his wife, Adele Wilby, an Australian citizen and former nurse he had married in 1978. She lived with him for years in Jaffna, the Tamils' heartland, and became a leader of the Tigers' women's section. Australia sought her arrest for violating a law that prohibits participation in foreign wars.

By the time he moved to London, Balasingham, known among activist Tamils simply as "Bala," was seriously ill with kidney trouble. The Tigers released a large number of Sri Lankan Army prisoners as a goodwill gesture in return for the Colombo Government ensuring his safe passage abroad. The gesture failed, and so the Tigers took Balasingham aboard one of their ships to Thailand, and from there he travelled to Singapore and on to London. No one expected to see him back in Sri Lanka.

When he did return for the 2002 peace talks the reunion with Prabhakaran was emotional. His influence over Prabhakaran was embarrassingly obvious at a packed press conference in Sri Lanka during the 2002 peace process. Balasingham knew about journalists, having been one himself for a Colombo newspaper before working as a translator at the British High Commission.

He was doubtless responsible for the image makeover of the Tigers leader. Eschewing his customary military fatigues and sidearm Prabhakaran attended the press conference in a safari suit and had even shaved off his moustache. After almost every question he would lean towards Balasingham to be primed with the reply, and for the most part Balasingham would do the replying for him. Which led one commentator to ask: "So who is the real leader of the Tamil Tigers?"

Balasingham died of cancer. He is survived by his wife.