Super-sized chocolate bars will be driven out of hospital shops and canteens under new targets to tackle obesity, the head of NHS England has pledged.

Hospitals will receive extra funding if they limit most sweets and chocolates on sale to a maximum of 250 calories, under the plans.

Simon Stevens said there was a need to fight the "super-size snack culture" as he set the new rules for sweets and chocolate sold in hospital canteens, shops and vending machines.

This means that most larger packs of chocolate and "grab bags" of sweets will be taken off the shelves.

The Royal Voluntary Service - the biggest hospital retailer across the UK - said that by introducing such schemes early, it had boosted sales of sushi and salad by 55 per cent, with fruit sales up by one quarter.

From next April, hospitals will be able to receive a share of a £150m “health and wellbeing” fund if they achieve new targets.

Under the rules, 80 per cent of sweets and chocolates on sale must contain 250 calories or less, and 80 per cent of sugary drinks must have less than 5g of added sugar per 100ml.

All food and drink sold in cafes, canteens, shops, kiosks and vending machines fall under the rules, which are an attempt to tackle obesity among NHS staff, and among the wider public.