Desperation was setting in among traumatised Haitians last night as they spent a second day in the open with no help in sight after the catastrophic earthquake that devastated their country.

Tens of thousands are feared dead and countless numbers remain buried under the rubble, their hopes for survival fading with every passing hour.

Among the thousands missing are 16 British nationals. Douglas Alexander, the International Development Secretary, said that only half of the 32 Britons living in Port-au-Prince had made contact with the UK's ambassador to Haiti.

"There are no indications of British casualties," he added.

As a massive international aid operation swung into action and the first planes bearing rescue workers and thousands of tonnes of aid landed on the island, fugitives from the disaster wondered if they could survive another day in the open with little food and only filthy water to drink.

Bodies lined the streets of the city, wrapped neatly in sheets and blankets, while others could still be glimpsed underneath rubble, dust-covered lifeless limbs protruding from twisted metal and crumbled concrete.

Scores were loaded on to trucks to be removed. But with many hospitals destroyed and morgues ruined, there was nowhere for the hundreds of corpses to go.

"It's the worst I've ever seen," Bob Poff, the Salvation Army's director of disaster services in Haiti, told CNN. "It's so much devastation in a concentrated area. It's going to take days, or weeks, to dig out."

The 7.0 magnitude earthquake, which struck just ten miles from the capital, Port-au-Prince, destroyed communication networks and knocked out the airport's control tower, adding to the difficulties of aid agencies.

Buildings including the presidential palace and the five-storey UN base crumbled, roads were blocked by rubble and trees, electric power was interrupted and water was in short supply. The only lights visible in the city came from solar-powered traffic signals.

Thousands of Haitians set up camp in parks and squares, too terrorised to return to the ruins of their homes. By last night the city's central Champs de Mars square resembled a huge open-air refugee camp – except it had no food, water or medecine.

Many refugees lay covered in dirt, bearing visible wounds and sporting makeshift slings or bloodsoaked cotton taped hastily over fresh injuries.