Iced versions of normal coffee such as frappuccinos contain so many calories that they increase people's chances of becoming overweight, the second biggest cause of cancer after smoking, according to the World Cancer Research Fund (WCRF).

A survey of iced coffees sold by high street chains Starbucks, Caffe Nero and Costa Coffee identified the worst culprit as the venti dark berry mocha frappuccino at Starbucks, which contains 561 calories. Even without whipped cream it still has 457 calories.

Health experts advise that a woman should consume about 2,000 calories and a man 2,500 calories per day to maintain a healthy weight.

"The fact that there is an iced coffee on the market with over a quarter of a woman's daily calorie allowance is alarming. This is the amount of calories you might expect to have in an evening meal, not in a drink," said Dr Rachel Thompson, science programme manager at the WCRF.

Having such drinks as an occasional treat is fine, she said.

"But if you are having them regularly then they will increase the chances of you becoming overweight, which in turn increases your risk of developing cancer, as well as other diseases such as heart disease and diabetes."

At Caffe Nero the double chocolate frappe and mocha frappe latte with semi-skimmed milk contains 483 calories, while the skimmed milk version has 452. At Costa Coffee, a massimo coffee frescato contains 332 calories, and a massimo iced mocha with full fat milk has 361.

A spokeswoman for Starbucks did not dispute the calorie counts produced by the WCRF but added that the company sold many low-calorie coffees.