The first flights carrying British aid to Afghanistan will now leave on Tuesday, a government spokesman said.

A civilian DC8 chartered by the Department for International Development was due to set off from RAF Manston in Kent on Monday night.

But a spokesman for DfID said the flight, bound for Mashhad in Iran, close to the Afghan border, had been delayed.

It will carry a cargo of 1,300 tents adapted for the harsh weather in the region as well as tarpaulin and plastic sheeting worth �400,000.

The 40-tonne consignment marks the first part of the government's �25m humanitarian aid package for the region.

The UN has warned of a major refugee crisis in Afghanistan and neighbouring countries as tens of thousands flee civil war, drought and the threat of US attacks.

Tony Blair has indicated he is keen to build a "humanitarian coalition" to deal with the refugee crisis in Afghanistan and on its borders.

Drought

He hopes the aid effort will match the international coalition being assembled to fight terrorism.

The Prime Minister discussed the humanitarian aspects of the crisis over the weekend during telephone calls with President Bush and UN Secretary General Kofi Annan.

Earlier, the first international food convoy to Afghanistan since the atrocities in New York and Washington DC reached the capital, Kabul.

Eight trucks carrying 221 tonnes of wheat made the difficult journey through to the city.

The World Food Programme normally feeds nearly two-thirds of Kabul's million-strong population.

Afghanistan is in the grip of a severe three-year drought which has left many people without the means of growing food.