Whether it's a trendy matcha latte or basic black filter coffee, hot drinks are a daily staple for millions of Britons. 

But new analysis might make you think twice before splashing the cash at certain popular high street chains.   

Experts at Which? have analysed the levels of caffeine in the hot drinks from five popular retailers – with astonishing results. 

Topping the list for caffeine is Costa's medium cappuccino, which contains a whopping 325mg – around the same amount as four 250ml cans of Red Bull, which contain 80mg each. 

In contrast, Pret's Matcha Latte contains the least caffeine, with just 28mg in a 355ml drink. 

'For many of us, there is nothing quite like a strong cup of coffee to start the day, but Which? found even matcha enthusiasts could be consuming more caffeine than intended,' said Jessica Carson, Which? health and wellbeing expert.

'Our research shows caffeine content varies wildly from chain to chain. If you drink multiple cups a day or need to cut back for health reasons, pay attention to where you shop and what you order to avoid any unwanted side effects.'

The Which? team analysed the amount of caffeine in popular drinks sold at Caffè Nero, Costa, Greggs, Starbucks, and Pret a Manger.

This included espressos, cappuccinos, filter coffees, flat whites, americanos and matcha lattes.

For reference, The British Heart Foundation advises up to 400mg of caffeine a day is considered safe for most adults. 

Overall, Costa's medium cappuccino was streets ahead of the competition. 

When it came to a single shot of espresso, Pret a Manger's offering was the strongest, containing 180mg of caffeine. 

That's four times as much as the espresso from Starbucks, which has just 45mg of caffeine.

In terms of matcha lattes, Costa's option again contained the most caffeine (99mg), while Starbucks' version contained 57mg – even more than a shot of espresso from the same chain. 

Which? said: 'This could be a shock for non coffee drinkers looking for jitter-free energy, especially if they are consuming more than one on an empty stomach.'

However, it was americanos that were found to have the widest spread of caffeine across the chains. 

At Starbucks, a medium americano contains 89mg of caffeine, while in Costa, the same drink contains a staggering 325mg. 

While caffeine is a natural stimulant that can make you more alert, health experts do not recommend having too much.

'Research shows that drinking 400mg or less caffeine a day should not affect your heart rhythm or increase your risk of abnormal heart rhythms (arrhythmias), such as atrial fibrillation,' the British Heart Foundation explains on its website. 

'You may find your heart rate increases slightly after consuming caffeine, especially if you’re sensitive to its effects.

'Some people also experience palpitations – when it feels like your heart is pounding or beating more quickly than usual – if they drink too much.'

The Daily Mail has contacted Caffe Nero, Starbucks, Greggs, and Pret a Manger for comment. 

A Costa Coffee spokesman said: 'At Costa Coffee, we're committed to helping customers make informed choices. That's why caffeine and nutritional information is available across our menu and online, so customers can choose the drinks that best suit their individual preferences and needs.

'We also offer decaffeinated coffee and a range of non-caffeinated drinks. Coffee naturally contains caffeine and levels can vary depending on factors such as the blend, recipe and serving size.'