David Cameron abandoned the usual Punch and Judy battle at prime minister's questions today to demand the government take action on the crisis in Darfur.
The Conservative leader visited the war-ravaged Sudanese region earlier this week and told MPs that anyone who went there "cannot fail to be horrified by what they see and what they hear".
He claimed 200,000 people have died in the past three years of fighting between black African rebel groups on one side, and government forces and the Janjaweed Arab militia on the other. A further two million had been driven into refugee camps, he said.
In a deal in the Ethiopian capital of Addis Ababa last week, the Sudanese government accepted a "hybrid" operation in Darfur made up of African Union (AU) troops, who are already in the country, and technical support from United Nations (UN) peacekeepers.
However, the government has expressed strong reservations to the UN sending in troops and it is unclear what will happen when the AU, whose 7,000 troops have had a difficult job in the region, pulls out at the end of the year.
Today Mr Cameron asked the prime minister what he was doing to ensure aid got through to some of the worst hit areas in Darfur, and demanded that pressure be put on the Khartoum government to keep to its obligations to reach a peace deal.
Mr Blair replied that the only way forward was to ensure the Addis Ababa deal was implemented - which included the Sudanese government upholding its promise not just to hold a ceasefire but also engage with rebel forces who have yet to sign a peace deal.
"The absolutely key thing is to get a significantly larger number of troops on the ground, backed up with proper logistics and support. [Mr Cameron] is absolutely right, it's a terrible situation, but the only solution is the one we've put forward," Mr Blair said.
Pressed further by the Tory leader, he added: "The Sudanese government should recognise that if they don't seize this opportunity it will be raised in the United Nations, the pressure will grow for strong measures against the Sudanese government.
"And I urge the African Union nations to get behind this concept of a hybrid force with the African Union and the United Nations, it's the only prospect we have of succeeding and we have to seize it now."
He said he would be speaking with Sudanese president Omar el-Bashir later today and would stress that unless his government cooperated, "we will have to look at tougher measures".