Professor R Sivachandran, a Central Committee member of Ilankai Tamil Arasu Kachchi (ITAK), told the Daily Mirror that only a system of devolutionary federalism would allow the fulfilment of Tamil aspirations in an interview this week.
A federal solution means “two tiers of government… each acting directly on their citizens,” said the professor. “Neither level of government should become dominant. One cannot dictate to the other on decision-making. One should not be legally subordinate to the other.”
“This system has been proved to be efficient and congenial, and it restricts the powers and promotes participatory democracy,” he continued. “The people far from the capital city will have greater access to wielders of power. A regional government will be able to focus on the particular concerns of the given area and act according to the wishes of people. It provides for shared rule at the centre and self-rule in the regions with dignity for people.”
The professor went on to reiterate his rejection of a unitary constitution for the island, stating that “these are not consensus and all-inclusive documents at all”.
Instead he called for a constitution which recognised the Tamil homeland in the North-East.
“There is no doubt that the North and East are the homeland of Tamil speaking people from time immemorial -- where their language, religions, culture and distinct traits followed for centuries,” he said. Before the settlement of people from other areas of the country through the state -sponsored colonisation schemes since the establishment of the Galoya Scheme in 1930s and other colonisation schemes, Tamil speaking people were the predominant majority in the North and East Tamil speaking people are the majority in the North and East, and they have a legitimate claim for their homeland as the Sinhala people in other provinces of Sri Lanka.  
See the full text of his interview here.