A third of drinks tested had the same amount or more sugar than Coca-Cola
There are "dangerously" high amounts of sugar in hot drinks regularly served in high street coffee shop and fast food chains, British research has found.
Action on Sugar analysed 131 drinks and found 98% would receive a red nutritional value label for high sugar content.
Starbucks' venti Grape with Chai, Orange and Cinnamon Hot Mulled Fruit was found to have the highest sugar content - a total of 25 teaspoons of sugar per serving.
Its venti White Chocolate Mocha with Whipped Cream had 18 and Signature Hot Chocolate had 15.
Costa's massimo eat-in Chai Latte contained 20 teaspoons of sugar, while KFC's mocha had 15 and Caffe Nero's drink-in Caramelatte had 13.
A third of all of the drinks tested contained the same amount or more sugar than Coca-Cola - which contains nine teaspoons of sugar per can.
Professor Graham MacGregor, chair of Action on Sugar, said: "This is yet again another example of scandalous amount of sugar added to our food and drink. No wonder we have the highest rates of obesity in Europe".
Researcher Kawther Hashem said firms needed to improve their labelling and stop selling extra-large serving sizes.
"These hot flavoured drinks should be an occasional treat, not an 'everyday' drink," she added.
A Starbucks spokeswoman said it was committed to reducing added sugar in its "indulgent drinks" by 25% by the end of 2020.
She said the chain also offered lighter options, sugar-free syrups and sugar-free natural sweetener.
Kerry Parkin, head of communications at Costa, said the firm had already taken significant steps to reduce the sugar content of its ranges.
"This April we will be setting salt and sugar reduction targets for 2020," she added.