How many chimneys in London does Santa need to go down?
The important starting figure isn't the population of London (9 million approx).
It's how many households are there?
The answer is in the latest outpourings of the English Housing Survey.
Number of households in London: 3,772,000
Next, how many of these households have children?
The 2021 census has that data, and it's approximately 35%. 35% × 3,772,000 = 1,320,000
Number of households in London with children: 1,320,000
This includes all 0-15 year-olds and 16-18 year olds in full time education so would seem to be an over-estimate for Santa purposes, but let's stick with it as an approximation.
Next, how many of these households have chimneys?
An important consideration is the age of London's housing stock.
The English Housing Survey has that information too.
Built
% of homes
Before 1919
28%
1919 to 1944
22%
1945 to 1964
13%
1965 to 1980
15%
1981 to 2002
10%
Post-2002
12%
I'm going to assume that only homes built before 1980 have a chimney.
This is a horrible generalisation but it gives us a ballpark figure of 78%. 78% × 1,320,000 = 1,030,000
Households in London with children and built before 1980: 1,030,000
Also chimneys tend to be a feature of houses, not flats.
The 2021 census has the required figures for London.
Type
% of homes
House or bungalow
54%
Flat or maisonette
46%
London has a lot of flats (in the rest of England it's 17% flats, not 46%).
But most of what was built before 1980 will have been houses, not flats, let's say 70%. 70% × 1,030,000 = 720,000
Houses in London with children and built before 1980: 720,000
Some households will be from cultures that don't follow the Christmas tradition.
In London about 25% of Londoners profess their religion to be Islam/Hindu/Sikh/Jewish.
But I still suspect a lot of them give presents on Christmas Day, so let's say only 10% don't. 90% × 720,000 = 650,000
Gift-giving houses in London with children and built before 1980: 650,000
Finally Santa only delivers to children who've been good.
But it's a cruel parent who actually goes through with holding back all presents.
So I'm going to say this last factor is irrelevant.
Number of chimneys in London Santa needs to go down: 650,000 (approx)
It's not as many as I first thought.
But it's still a heck of a lot to visit in one night flat.
