Can you please point to any city across the world that has a successful obesity strategy which has seen rates of obesity fall as a direct consequence of the policy?

Across the globe, there is great interest in some of the work we are doing here in London to tackle childhood obesity – especially as much of our work is focussed on creating healthier local environments, which benefit not only children but the whole community, and which should have long lasting impacts.

Increasing rates of obesity remain a complex and long-term global challenge. There is no silver bullet to tackling obesity and our health and care systems in London are different to other cities across the world, so a direct comparison is difficult.

Research into city-wide approaches to address obesity has found that multi-component initiatives involving every sector are needed, with interventions working across the individual, community and city levels.

Work on these issues is being taken forward through my health inequalities and other strategies and our recovery missions. We’re working to create healthier environments in the most disadvantaged areas, with a commitment that by 2024 children and young people will find it easier to eat healthy food and be more active where they live, learn, shop, work and play.

My ground-breaking policy to introduce advertising restrictions on the TfL estate has been associated with an estimated 95,000 fewer cases of obesity – that’s almost 5 per cent fewer people with obesity within the first year the policy was implemented.

As a global city London is keen to look across the world to share best practice, learn from other countries and build an evidence base for action. London is a member of the Partnership for Healthy Cities, a global network of cities that are committed to preventing noncommunicable diseases, including obesity.

Next March I will be co-hosting a Partnership for Healthy Cities summit for Mayors and participants from over 60 cities to meet and learn from each other.

I have also convened a new Mayoral Advisory Group to advise on child healthy weight. The experts on this group will share learning on tackling obesity that will inform our future work.