On a wing and a prayer in Sri Lanka: David Cameron ventures on to a diplomatic sticky wicket over country's human rights record

PM will meet the Sri Lankan President, Mahinda Rajapaksa, before the Commonwealth summit opens in Colombo

Prime Minister David Cameron meets staff at Air Radio in Kolkata, India, following his interview by the radio station (PA)

As diplomatic ice-breakers go, talking about your host country’s favourite son is a good place to start. So David Cameron’s loosener with the Indian Prime Minister, Manmohan Singh, in Delhi, as Sachin Tendulkar began his final Test match, was easy.

Praise for the Little Master eased otherwise-tense talks about today’s Commonwealth Heads of Government Meeting, which Mr Singh is boycotting as a result of the host country Sri Lanka’s refusal to investigate the deaths of up to 40,000 Tamils in the final stages of its civil war in 2009.

Yet when Mr Cameron meets the Sri Lankan President, Mahinda Rajapaksa, before the summit opens in Colombo, it is doubtful that a similar approach involving Muttiah Muralitharan will work, given that the spin bowler is a Tamil. Never in 40 years of Commonwealth summits has a British Prime Minister faced such a diplomatic showdown with a host leader as Mr Cameron faces.

Today he said that he would use his meeting with Mr Rajapaksa to warn him that those responsible for alleged war crimes against the Tamils must be held to account, and the failure to hold a legitimate independent inquiry risks undermining his credibility. Mr Cameron will travel to the north of Sri Lanka to meet the country’s Tamil minority – the first international leader to do so in 65 years – before his expected showdown with Mr Rajapaksa on Friday night.

The Prime Minister has been heavily criticised for even being in Sri Lanka given that his counterparts from Canada and Mauritius have joined Mr Singh in boycotting the event. In an effort to deflect the barbs, Mr Cameron has said he will carry a tough message to Colombo after his talks in Jaffna.

Speaking in Calcutta before flying to Colombo, Mr Cameron said the film No Fire Zone, which revealed evidence of war crimes allegedly committed by government forces, contained “chilling images of appalling acts [that] need to be properly investigated”.

“The war is over; that is good for Sri Lanka, but you never get true reconciliation unless you deal with human-rights abuses both now and in the past,’’ he said.

David Mepham, the UK director of Human Rights Watch, was one of those for whom the Prime Minister’s words were not enough. “Cameron’s sense of outrage is too little and far too late,” he said. “But it perhaps creates an opportunity to salvage something from an otherwise thoroughly discredited meeting, that he is clearly so determined to attend.”

Kate Allen, director of Amnesty International UK, added: “There’s much to speak out on – impeached lawyers, silenced journalists, alleged war crimes. [Mr Cameron] now needs to follow through on his promise to hold Sri Lanka’s feet to the flame. We welcome the news he will be travelling to the north of the island and meeting the families of people who have been ‘disappeared’ for opposing the government. He must also ensure people who speak to him don’t face reprisals for doing so.”

But Ed Miliband, the Labour leader, repeated his opposition to Mr Cameron’s presence in the country because of its “lamentable human rights situation”. He said the Prime Minister should now set out “a clear UK action plan to support tangible improvements in human rights in Sri Lanka”.

Diplomatic hostility between London and Sri Lanka has intensified in recent days, leaving open the prospect that Mr Rajapaksa could even cancel today’s talks at the last minute. Sri Lanka’s information minister, Keheliya Rambukwella, this week accused Mr Cameron of displaying a “colonial” attitude with his demands for a war crimes investigation.

Foreign journalists, including Channel 4 reporters, have been banned from travelling to northern Sri Lanka as part of an attempt by the government to keep the focus on the summit and away from the war. Mr Rajapaksa said his country had “nothing to hide” and could defend itself against allegations. “I will be meeting [Mr Cameron] and … I will also have to ask some questions,” he said.

David Cameron tries some snacks from a stall in Calcutta before his visit to Sri Lanka (PA)

“We have a legal system in Sri Lanka. We have a human rights commission, now the Commonwealth is ready to strengthen it. If anyone wants to complain about a human rights violation in Sri Lanka – whether it be torture, whether it be rape – we have a system. If there are any violations, we will take actions against anybody. People were getting killed for 30 years, at least after 2009 we have stopped it. There is no killing in Sri Lanka today.”

In their talks, Mr Cameron will say that the closed, military-led 2013 Courts of Inquiry process was insufficient, and that if Sri Lanka does not stage a credible inquiry then the international community will launch its own. He tweeted: "I will be clear with the Sri Lankan President Rajapaksa: it's time the appalling and chilling events in his country are investigated."

While in Jaffna, the PM will visit the Tamil Uthayan newspaper to hear about the intimidation they face.

Mr Cameron said: “Part of my message to President Rajapaksa is he should be seizing the opportunity to win the peace. There are some very serious questions that need to be answered, questions about human rights violations today in Sri Lanka. We are two sovereign governments, this is 2013, and we should have these sorts of frank conversations.”

He added: “Is the Commonwealth a perfect organisation? No it isn’t, has it on occasion taken action against countries that have fallen short in the past, such as Zimbabwe and elsewhere? Yes it has.”