Supermarket Battenberg cakes contain more sugar than all the other ingredients put together, according to new research.

And almost half a Genoa and Red Velvet cakes are just the sweet stuff, warn campaigners.

Almost all cakes (97 per cent) and 74 per cent of biscuits contain 22.5 grams of sugar in every 100, according to the research, enough to earn them a 'red label'.

But the amounts differ widely - showing it is possible to to reach the Government's reduction targets, say campaigners.

The average sugar content in cakes was 36.6g/100g - with Battenberg having the highest, a staggering 56.4g/100g.

This was followed by Genoa (45.9g/100 g) and red velvet cakes (44.2g/100g). Blueberry muffins (24.6g/100g) contained the lowest.

For cookies, iced biscuits (43.5g/100 g) contained the highest amounts of sugar and shortbread (17.5g/100 g) the lowest.

The study also found there was a large variation within the same category of cake.

For example Victoria sponges and similar products ranged from 23.4 to 59.2g/100g.

Researchers who conducted the study, published in BMJ Open, said it shows reformulation can easily be achieved They found a slice of Victoria sponge can have as little as 11.9g sugar or 34.3g - a difference of 6 teaspoons.

Similar to sugar, there was also a large variation in energy/calorie content between different categories of cakes.

On average, plain sponge with chocolate (446 kcal/100g) contained the highest amount of energy.

Again, there were large variations within the same category. Chocolate Swiss rolls ranged from 366 to 500 kcal/100g.

The McVitie's product range contained the highest average sugar (43.1g) and Premier Foods contained the highest energy (424 kcal) per 100g.

Study co-author Kawther Hashem, a registered nutritionist for Action on Sugar at Queen Mary University of London, said: "This research clearly shows the levels of sugar and calories in products can be reduced since there was a large variation in sugar and calorie content within the same category of cakes and biscuits.

"Yet, worryingly, not all manufacturers are complying.

"If some manufacturers can produce chocolate cake bars with 22% fewer calories per 100 g, so can others."

There was also a large variation in sugar content within the same category of biscuits. Breakfast biscuits ranged from 12.0 to 30.9g/100g form instance.

The average energy content in biscuits was 484 kcal/100g. Shortbread biscuits with added ingredients contained the most (528 kcal/100g) and fruit-filled biscuits (391 kcal/100 g) the least.

Among jam and cream biscuits calorie content ranged from 425 to 558kcal/100g.

Fox's products had the most average sugar content (35.8 g/100 g).

Dr Schar products, sold at Aldi supermarkets, had the highest average energy content (512 kcal/100 g).

In 2016, the government's sugar-reduction programme was launched, where food and drink companies were asked to reduce sugar in their products by 20% by 2020 by reformulating products or reducing portion size.

Study co author Prof Graham MacGregor, Chairman of Action on Sugar, said: "Large amounts of cakes and biscuits are consumed in the UK so a reduction in the amount of sugar and calorie content could play an important role in helping prevent obesity and tooth decay.

"The majority of the food and drink industry in the UK have asked the Government for a more robust and mandatory programme of reformulation. It is a tragedy for our children that this has not been done."