Tagore is part of a five-member MP-group scheduled to meet the British Prime Minister here tomorrow.
"The Sri Lankan government has failed to act on the requests of India and several other countries to set for an independent investigation into the alleged excesses of the Eelam war between the Lankan Army and the LTTE," Tagore said.
"The excesses were committed by both the Sri Lankan forces and the LTTE," the MP further alleged.
Cameron would be visiting Jaffna in the north of the Island Nation before travelling to Colombo for the Commonwealth Heads of Government Meeting starting Friday.
More From This Section
The Congress MP said that he would also request the British PM to take up the issue of devolution of powers for ethnic Tamils in Sri Lanka, as per the 13th Amendment.
Under the Rajiv Gandhi-Jayawardene Accord, Tagore said, Sri Lanka should empower the elected provincial Government with Land and Police rights.
He said that though an elected government with a Tamil Chief Minister in Jaffna was a good beginning, however, the international community should ensure that the rights of the Tamils staying in Sri Lanka are not violated.