An emergency relief flight bound for Haiti has taken off from Heathrow Airport, a British Airways spokesman said.
The Boeing 747 carrying 50 tonnes of supplies left at about 8.30am on Saturday crewed by a team of 30 volunteer BA pilots, cabin crew, engineers and ground staff.
The flight, with 10 tonnes of Oxfam cargo, will stop en route at Billund in Denmark to pick up 40 tonnes of aid from Unicef, BA's charity partner. It is expected to land in the Dominican Republic at about midnight GMT.
A BA spokesman said seats had been removed from economy class to make room for the cargo, which includes containers of water, purification equipment and pumps. As well as funding the £250,000 cost of the flight, BA has pledged £300,000 from its Unicef Change for Good programme.
A British Red Cross emergency logistics team was also flying to the Dominican Republic on Saturday to help co-ordinate emergency supplies arriving in neighbouring Haiti. International aid was flooding in to Port-au-Prince's airport, which is now controlled by the US military, but logistical problems and the country's shattered infrastructure meant much of it was failing to reach people.
Meanwhile, the man in charge of the UK search and rescue team that pulled a two-year-old girl from a collapsed building on Friday said they would "continue to help as best we can". Mike Thomas said: "We have been exceptionally busy, but it is rewarding to be able to do the job we were sent to do. We hope that ... we will continue to help as best we can."
That rescue provided a fleeting moment of joy amid the desperation and chaos in Haiti as aid workers struggled to get adequate supplies to survivors of the devastating earthquake. Anger mounted at the lack of meaningful aid nearly four days after the disaster, with reports of looting, fights over food and water and machete-wielding gangs roaming the streets of the capital Port-au-Prince. Fears were also growing for people still alive in the wreckage as rescuers continued their desperate search for survivors.
Relatives of a missing British woman said they feared the worst. United Nations worker Ann Barnes, 59, has been unaccounted for since the building she was in collapsed. UN Secretary-General Ban Ki-Moon said 100 UN staff who were in the collapsed headquarters building in Port-au-Prince, had not been found. The total number of missing UN workers reached nearly 200, with 36 confirmed dead.
The Red Cross estimated the death toll was between 45,000 and 50,000 but it is thought millions more have been injured, orphaned or made homeless. Aid workers reported seeing piles of bodies in the streets and children sleeping among the dead, while the grief-stricken try to dig their relatives from the rubble with their bare hands.
On Friday Prime Minister Gordon Brown reassured donors that their money would get through after meeting staff at the Disasters Emergency Committee (DEC) in north London. Britons donated more than £2 million within 36 hours of a DEC appeal being launched.