In Chelsea, a makeshift morgue

They lie side by side in a mass grave - two small children and four adults, possibly their parents and grandparents. In a cruel corruption of a family snapshot, the six bodies await burial in a field in Wat Bang Muang, Thailand.

It is a heart-rending image that seems to sum up the utter devastation wrought by the Asian tsunami.

And the scale of the tragedy was brought home to London today with the setting up of a makeshift morgue in Chelsea.

Here, emergency procedures for a terrorist attack are being employed to deal with the dead.

In Wat Bang Muang, as the Thai authorities struggle to cope, burial has been reduced to a purely clinical procedure - there are no coffins or quiet ceremony, just plastic sheeting and noisy bulldozers.

Row upon row of dead have been lined up by masked officials, the DNA tags that have been used to identify them still visible.

The mass graves provide the answer to UN secretarygeneral Kofi Annan's anguished question after touring part of the stricken region today: "You wonder, where are the people? What has happened to them?"

In Thailand, they have lost more than 5,000 people and 4,000 are still listed as missing.

In Indonesia, visited by Mr Annan this morning, the toll has breached the 100,000 mark. And still the numbers keep rising hour by hour by hour as more bodies are pulled from the rubble of fishing villages, farming hamlets and tourist resorts.

Mr Annan and World Bank President James Wolfensohn flew over Indonesia's west coast in a Singaporean helicopter and then drove to the shattered coastal town of Meulaboh, where families picked through piles of rubble 6ft high.

"I have never seen such utter destruction mile after mile," Mr Annan, visibly shaken, told reporters.

In New York, the UN's relief coordinator Jan Egeland warned: "I think we have to be aware that very, very many of the victims have been swept away and many, many will not reappear. The 150,000 dead figure is a very low figure. It will be much bigger."

The bodies of Britons recovered in the disaster region have so far been sent to the mortuary in Chelsea in line with the blueprint created to deal with a terrorist attack.

"These plans were drawn up after 9/11 to cope with a major disaster in central London," said a Home Office official. "We are following the same procedures as we would for mass fatalities in the centre of London."

Although the mortuary has so far received only 19 bodies from the tsunami, a team is on duty 24 hours a day. It includes a dental expert who has identified most remains but also facilities to identify victims through DNA samples.