DAVID Cameron is today due to have a showdown with Sri Lankan President Mahinda Rajapaksa over the "chilling" claims of human rights abuses by the government of the South Asian country.

This is despite warnings from Colombo that it would not be lectured at during the summit of the Commonwealth heads of government (Chogm).

Whitehall sources have made it clear that there would be a good deal of anger if the expected bilateral meeting between the two leaders did not take place. The Prime Minister has brushed aside calls that he should have boycotted the summit, insisting he would use his visit to challenge the Sri Lankan government over the abuse allegations.

"You can't make the arguments unless you are there," he declared.

Mr Cameron promised a "frank exchange of views" with his host, saying: "There are some important points to put to the Sri Lankans.

"There is the problem of human rights as we speak today; the people who have disappeared, the lack of free rights for journalists and a free press."

Yet Mr Rajapaksa fended off criticism, telling reporters in Colombo: "We are open. We have nothing to hide. If anyone wants to complain about human rights violations in Sri Lanka, whether it's torture, whether it is rape; we have a system. If there are any violations, we will take actions against anybody. I am ready to do that."

Today Mr Cameron aims to travel to the conflict-scarred north of Sri Lanka to meet journalists and campaigners from the Tamil community, who have complained of abuses by security forces during and after the bloody repression of a 26-year civil war in 2009. The United Nations estimates at least 40,000 were killed during the suppression of the Tamil Tigers.

No 10 said it did not feel the summit would throw up calls to boycott the Commonwealth Games in Glasgow.