The proposal is to ban all advertisements for "unhealthy" food and drink, as defined under the Food Standards Agency Nutrient Profiling Model (the same rules used by Ofcom to regulate advertising on children's television).
But how great might the impact of the Mayor's policy actually be? To find out, I took a trip round London to see how much junk food advertising there actually is on the TfL network. And, spoilers, there isn't anywhere near as much as you might think.
I started off in Bow.
The bus shelter at Bus Stop M has 0 adverts.
The bus shelter outside Bow Church station has 2 adverts, neither for junk food.
Bow Church station has 8 adverts, none for junk food.
So far that's ten adverts, none of them for junk food. I should point out that I'm not including "TfL adverts" in my counts, for example I've ignored anything that just says "Why not use contactless?" or "Hold The Handrail".
Bow Road station has 68 adverts. None are for junk food.
Specifically that's 0 adverts in the ticket hall, 15 adverts on the platforms, 18 adverts on the eastbound staircase and 35 adverts on the westbound staircase. Four of these (on the westbound staircase) are for an Almond Protein Ball which, if I've interpreted the nutritional instructions properly, is sufficiently nutty not to count as "less healthy". Hence the big zero.
Next I caught a District line train and walked the length of it.
One District line train contained 139 adverts. None were for junk food.
Seriously, not a single one, not even borderline. Is the Mayor overplaying how much of a serious problem this is?
Mile End station has 7 adverts. One is for junk food.
I was expecting more adverts at Mile End, but no. There are none on the platforms, and the majority are housed in a rolling display halfway down the stairs from the street. One of these is for Dextro Energy orange sticks, which are essentially just sugar in a wrapper, so they'd definitely get the boot if the Mayor's ban came in. But that's all.
Becontree station has 7 adverts. None are for junk food.
Dagenham Heathway station has 1 advert. It is not for junk food.
Dagenham East station has 13 adverts. None are for junk food.
One of the adverts at Becontree is for Beefeater Pink Gin, but alcohol is specifically excluded from the regulations. The only advert at Dagenham Heathway is for an exhibition at the Barbican. Banning junk food adverts from the tube is unlikely to affect Barking and Dagenham, because there aren't any.
But it's a different story on Barking and Dagenham's bus shelters.
Both bus shelters outside Becontree station have 2 adverts. Both are for junk food.
Both bus shelters outside Dagenham Heathway station have 2 adverts. None are for junk food.
None of the bus shelters on the road between Becontree and Dagenham Heathway have any adverts.
The 12 bus shelters along Ripple Road include at least 8 adverts for junk food.
Becontree's adverts are for Cadbury's chocolate bars and a carbonated multivitamin fruit drink. Neither of these pass the junk test. Dagenham Heathway's adverts include one for Tilda rice, which is fine. As for Ripple Road, which is essentially the A13, I spotted 4 adverts for McDonalds and 4 adverts for Milky Way chocolate. One of the McDonalds adverts was outside a McDonalds. There were no KFC adverts outside the KFC.
On the way back into town I took the DLR from Beckton to Bank.
Beckton station has 12 adverts. None are for junk food.
The 14 stations between Beckton and Bank have at least 150 adverts between them. I saw only 4 for junk food.
All four of those adverts were for Dextro Energy orange sticks. No other forms of junk food appeared. Most of the adverts across the DLR seem to be for online clothing retailers. The same few adverts appear over and over at all the stations, including film, theatre, Westfield and a budget airline. Nobody is flogging fizzy drinks, burgers, chocolate or ice cream on the DLR.
There are a lot of adverts at Bank station. For example...
On the DLR platforms, 1 junk food advert (Dextro Energy)
On the Northern line platforms, lots of adverts, none for junk food.
In the passageways between the platforms, 1 junk food advert (Dextro Energy).
On the eastbound Central line, 34 adverts, none for junk food.
On the westbound Central line, 30 adverts, none for junk food.
Up the escalators, 6 electronic adverts, none for junk food.
To summarise, after tracking down well over 100 adverts within Bank station, only two were for junk food. There's nothing significantly unhealthy here.
There are a heck of a lot more adverts at Chancery Lane station.
On the eastbound Central line platform, 50 adverts, none for junk food.
On the lowest escalator, 56 adverts, none for junk food.
On the westbound Central line platform, 42 adverts, none for junk food.
On the middle concourse, 20 adverts, none for junk food.
On the upper escalator, 90 adverts, none for junk food.
To summarise, there are over 250 adverts at Chancery Lane station, absolutely none of which are for junk food. Meanwhile in the ticket hall is a Lola's Cupcakes store, which is about as unhealthy as you can get, but presumably TfL are happy to continue collecting their sugar-based rent, no questions asked.
Shall we try Oxford Circus station next? Deep breath.
On the eastbound Central line platform, 40 adverts, none for junk food.
On the westbound Central line platform, 30 adverts, none for junk food.
On the northbound Victoria line platform, 30 adverts, none for junk food.
On the southbound Victoria line platform, 35 adverts, none for junk food.
On the northbound Bakerloo line platform, 40 adverts, none for junk food.
On the southbound Bakerloo line platform, 40 adverts, none for junk food.
Are you getting the picture yet?
I also walked lots of the connecting passageways at Oxford Circus, and rode some of the escalators, past at least 300 more adverts. Just eight of these were for junk food, all of them for Cocoa Loco, a "decadent chocolate ganache topped with caramelised hazelnuts." It's not aimed at children, but would definitely be banned under the new regulations because its nutritional composition smashes the limit. But that's all. Out of well over 500 adverts, a piddling eight are for posh chocolate.
But then there are the ticket gates, and they're nutritionally evil.
All the ticket gates at Oxford Circus are emblazoned with McDonalds adverts, as a hint that passengers might want to go stuff their face with cheap fat and liquid sugar at the earliest opportunity. These'd be instantly removed if ever the Mayor's ban came in... and McDonalds would presumably revert to advertising on telephone boxes and lampposts, like they are outside.
While I was outside on Oxford Street I made time to check on the buses. 16 went by, and none of them were advertising junk food on the side. During the day I also took a ride on four buses, both here and in Dagenham, and found absolutely no junk food adverts inside. Loan companies yes, evangelical religions yes, but Haribo no. Meanwhile...
On Oxford Street, four bus shelters had scrolling panels advertising McDonalds.
On High Holborn, two bus shelters had scrolling panels advertising Burger King and Cadbury's.
Across London there are a lot of bus stops without bus shelters, and a lot of bus shelters with no adverts, but it does seem as if bus shelters have the greatest concentration of TfL's junk food adverts. Scrapping all of those might just make a difference, by preventing children being enticed by sugar and stodge. Let's do that, let's do that soon.
On the tube and DLR, and inside trains and buses, scrapping junk food adverts wouldn't have much effect because there are hardly any of them. Overall I went to 24 stations and saw well over 1000 adverts, but fewer than 20 of these were for junk food. With stations in mind, it does look as if this Mayoral policy has been vastly over-hyped. But out on the streets it could be a very different matter, and surely there's no reason not to embrace this ban in full.