A politician has raised doubts about whether plans set out by Sadiq Khan to make London healthier will work.

Yesterday, the London Assembly questioned Mr Khan’s representative on his food strategy.

The draft plan is a document that sets out how the mayor will ensure that every Londoner has access to healthy and affordable food inside and outside of their homes.

But Labour party assembly member Onkar Sahota raised concerns that even if people had the option between healthy and unhealthy food a lot of the time they would still choose the unhealthy option.

He said: “The cost of an apple is less than the cost of a bar of chocolate so why do people buy the bar of chocolate instead?”

“How will the strategy change people’s behaviours towards unhealthy food?”

Claire Pritchard, chairman of the London Food Board- the team that worked with the mayor to develop the strategy – said that the barriers to eating unhealthily such as people earning under the living wage needed to be addressed.

Ms Pritchard said: “Our overall priority is making sure every Londoner has access to a healthy and affordable diet.”

She also added that the London Food Board was not solely responsibility for problems such as childhood obesity and blamed advertising for the “powerful role” it plays.

But, Mr Sahota was not convinced that her answer really addressed how the strategy would stop people actually choosing to eat unhealthy food.

He said: “We need something concrete to make people eat healthily and I’m not sure this strategy understands that.”

The strategy says that London’s obesity problem is “compounded by a food environment that bombards Londoners with the marketing and promotion of unhealthy food”.

Last month figures from the Local Government Association revealed that 23.6 per cent of year six children in London are obese and 10.3 per cent in reception are obese.

Mr Khan has already taken steps as part of this plan to tackle childhood obesity, such as banning junk food adverts at Transport for London (TfL) networks.

But the strategy also highlighted that not everything to improve healthy eating is within the mayor’s powers and says that retailers should promote more healthy food options.

Caroline Russell, Green party assembly member, was quick to agree with this and pointed out that to make sure children eat better we need to look at the role of supermarkets.

She said: “Big businesses and supermarkets don’t have a public purpose at their heart.

“We need to find a way to stop those businesses thinking about their profits and pushing them to be thinking about the good of the community.

“Their business model is driving obesity levels in communities.

Ms Russell added: “At the moment the power of those businesses is just accepted, politicians really need to be thinking about that.”