Around 30 passengers were rescued after a blaze broke out on a tour boat on the River Thames, emergency services said.
Flames ripped through the vessel on a stretch of water close to Lambeth Bridge.
Passengers were hauled to safety by crews on passing tour barges after the fire broke out shortly before midday on Sunday.
London Fire Brigade said the beleaguered boat was 33% damaged by the blaze.
"Approximately 30 people were rescued by passing tourist boats," a spokesman said.
"All persons were accounted for."
Many on board the London Duck Tours boat jumped into the water as flames took hold and thick black smoke billowed from the amphibious vessel.
A woman and a child were taken to hospital with suspected smoke inhalation.
Further tourists were treated at the scene of the fire, opposite the Houses of Parliament.
A police source said the nature of the injuries "could have been a lot worse".
"A number of people were reported to be in the water at the time. Several Metropolitan Police units attended including the Marine Policing Unit and the police helicopter.
"A number of people were recovered from the water. All 28 passengers and two crew members have been accounted for.
"The emergency services are in attendance at the scene."