These will be paid for by the Children's Health Fund, launched in 2015 by Sustain and funded by a 10p levy on drinks with added sugar in over 130 of the UK’s leading restaurants, cafes and coffee shops.

The Fund has announced that it has raised over £50,000 so far and is now open for applications, with awards being made twice a year and the first round focusing on improving children’s access to tap water. Campaigners hope that access to free drinking water will discourage young people from buying unhealthy sugary drinks.

Gloria Davies-Coates, Children’s Health Fund manager, said “Promoting access to tap water is the obvious flipside to encouraging less consumption of drinks with added sugar. There’s so much more that could be done to ensure that drinking water is more convenient to kids when they’re out and about, making it the default for thirsty active children.”

Restaurants including Leon, Abokado and Tortilla have introduced the 10p levy in their own restaurants and Leon alone has raised £50,000 since the introduction in its 130 restaruants.

John Vincent, of Leon, said “Our addiction to sugar is making us sick and costing the NHS billions every year. We know that our children are consuming far too much sugar.  Even one can of a fizzy drink takes them over their recommended daily intake.

“In four months we’ve raised enough from our sugar tax to give thousands of children access to free, healthy water in their local park. Just think what could be achieved if the Government introduced a national tax and invested that back in our children’s health.”

Ben Reynolds, Deputy Coordinator of Sustain, who are campaigning for a national sugary drinks duty continued, “We’re showing Government that this tax for good is really working, and is really going to make a difference for children across the country.

“But a handful of restaurants doing this is no substitute for Government action. The public support this and Mr Cameron has said this option is definitely on the menu. Now let’s put it into law.”