The travellers were stranded because of a curfew and ban on traffic leaving or entering the city, imposed after a day of violence on the streets of the capital.
Embassy staff drove the tourists in a four-vehicle convoy - escorted by police - past barricades, army patrols and violent street scenes to a Kathmandu guest house.
The Foreign Office is advising tourists to avoid Nepal following riots sparked by the crowning of Prince Gyanendra, the country's third king in four days.
British Ambassador Ronald Nash said an estimated 100 UK tourists remain in Nepal, but added that embassy staff were keeping a close eye on the situation.
Two Gurkhas returning from a UK reunion were also evacuated from the airport, but rioters pelted their vehicle with stones as they were driven through the city by soldiers.
Four embassy staff members, including the consul and vice-consul, picked up 23 Britons, two Canadians and a Bengali from the airport.
'5am curfew'
Mr Nash said: "The police were going to bring them out but it would have taken around two or three hours, so we sent up a little convoy of Land Rovers.
"There were also a few people who might have been stuck at the roadside in buses or overnight, because the curfew goes on until 5am.
"But we have got them and it means we should have put everybody to bed now."
Earlier, British Army Gurkha soldiers paid their respects to the dead members of the Nepalese royal family.
A service was held at the 2nd battalion of the Royal Gurkha Rifles army barracks at Shorncliffe, in Folkestone, Kent, where more than 1,000 Nepalese Gurkhas are based.
It followed Friday's palace massacre which left at least eight members of the royal family dead.
The Gurkhas at the Sir John Moore barracks, where flags are flying at half mast, are said to be in a "state of shock".
About 800 soldiers laid posies in front of pictures of King Biendra and Queen Aiswarya during Monday's service.
A Union flag and a Nepalese flag were draped either side of the portraits.
Army spokesman Paul Beard said many of the soldiers will still unable to comprehend what had happened.
"There is a deep feeling of shock and sadness here. It has come as a bitter blow to everybody that this has happened in their peaceful country.
"I don't think many have come to terms with what has happened."
The Queen has instructed that flags fly at half mast at Royal palaces, main government buildings and military sites across the UK.
New monarch
The newly-crowned King Gyanendra promised to investigate the circumstances of the killings in his first address as monarch.
The slain king's son, Dipendra, died early on Monday, after three days in a coma.
Dipendra, who was said to have shot his father, mother and other family members following a dispute over his choice of bride, was initially blamed for the murders.
This account was later denied, with an official statement speaking only of the sudden discharge of the weapon inside the royal palace.
Nepal is a big draw for UK travellers and has a significant resident British population.