More people in the capital have signed up to donate their stem cells than residents in any other part of Britain - d espite Londoners having an unfriendly reputation .
Blood cancer charity Anthony Nolan has mapped its bone marrow register for the first time, showing the proportion of people in each region who are signed up to the bone marrow register.
The charity said that more than 80,000 people in the capital are now signed up to the register - 0.97% of London's population.
A spokeswoman said that other "selfless hotspots" are the East Midlands, where 0.91% of the population has signed up, Scotland where 0.89% of people are on the register and in the south east where 0.87% of people have pledged to donate their stem cells.
Places with the lowest rates of sign-ups are the West Midlands and the south west, where just 0.66% and 0.65% of people, respectively, have signed up to the register.
The register was set up 40 years ago to help find lifesaving matches for people with blood cancer who desperately need a stem cell, or bone marrow, transplant.
Ann O'Leary, head of register development at Anthony Nolan, said: "Donating stem cells to save the life of a stranger is a remarkably selfless act so it's great to see so many Londoners challenging the city's stereotype and signing up to our register.
"Two thirds of patients will not find a matching donor from within their families; instead they turn to Anthony Nolan to find them an unrelated donor.
"Even though London has the highest proportion of donors of any region, it's still less than one per cent of the overall population of London, which shows us that we urgently need to recruit donors from all over the UK so we can give people with blood cancer the best possible hope of a cure."
Ms O'Leary added: "Mapping the register in this way will help us to target our efforts in order to grow the register and save more lives.
"We now need people all over the UK to join the fight against blood cancer and champion the register at a local level - as we know it works."
:: People aged 16 to 30 can sign up to the Anthony Nolan bone marrow register. To find out more visit www.anthonynolan.org.