Whether it's a classic Chicken Club or a fresh Salmon & Cream Cheese, sandwiches are a lunchtime staple for millions of Brits. 

But a new study might make you think twice before choosing certain sandwiches in your next meal deal. 

Experts from Action on Salt & Sugar have revealed the popular options that contain dangerous amounts of salt. 

Of the 546 sandwiches, wraps, rolls and baguettes analysed by the researchers, almost half (44 per cent) carry a red 'high' salt warning on the front of the packaging.

The worst offender is GAIL's Smoked Chicken Caesar Club, which contains a whopping 6.88g of salt. 

To put that into perspective, that's the equivalent of nearly 10 rashers of bacon, or five McDonald's Cheeseburgers!

What's more, this popular sandwich contains 1,067 calories – more than half the daily calorie limit for women. 

'Most people choose sandwiches for lunch for their simplicity, convenience and affordability. But what they're actually eating can be a full day's worth of salt hidden between two slices of bread,' said Sonia Pombo, Head of Research and Impact at Action on Salt & Sugar.

While salt is brilliant for boosting flavours, too much can cause high blood pressure, which increases the risk of heart attacks and strokes.

The NHS recommends adults have no more than 6g of salt per day, yet many people unknowingly exceed this. 

'Around three quarters of the salt we eat comes from packaged and everyday foods we buy, such as bread, breakfast cereals, meat products and ready meals,' the NHS explains on its website. 

'It can also be found in takeaways, restaurant or café meals and fast–food outlets.'

In their new analysis, the team set out to analyse the salt levels in popular sandwiches.

In total, they looked at 546 sandwiches, wraps, rolls and baguettes sold in supermarkets and high street chains in the UK. 

Overall, 12 per cent of the sandwiches were found to exceed salt targets. 

While GAIL's Smoked Chicken Caesar Club was by far the worst offender, this was followed by another GAIL's offering – the Smoked Salmon Bagel with Schmear and Pickled Pink Onions, which contains 4.2g of salt. 

The Daily Mail has contacted GAIL's for comment.  

PAUL's Rosette Cheese Salami Gherkin (4.19g) was close behind, ahead of Pret A Manger's Ham & Grevé Baguette (3.85g), and Subway's Spicy Italian Wrap (3.8g). 

Other popular sandwiches on the list include Tesco's Fully Loaded Hot Honey Halloumi, Falafel and Pickled Slaw (3.78g), Tootoomoo's Sriracha Pork Sando Sandwich (3.7g), and Sainsbury's Kitchen Deli Pastrami, Cheddar Cheese & Gherkin Mustard Mayo (3.67g).

At the other end of the list, Subway's Veggie Delite Sub was found to be the least salty offering, with just 0.60g of salt. 

Pret a Manger's Avo, Olive & Toms Half Baguette is also a great low–salt offering at 0.82g, along with Caffè Nero's Chicken, Tomato & Basil Hot Wrap (1.08g), and Greggs' Tuna Mayonnaise & Cucumber Sandwich (1.1g). 

In terms of specific outlets, the researchers highlight that several companies are getting it right. 

Their analysis found that every product from Pollen + Grace, The Gym Kitchen, and Urban Rajah met calorie and salt reduction targets, and had no red warning labels on front of pack. 

Within retailers, Asda and Lidl achieved full compliance to the salt targets for sandwiches. 

Meanwhile, Starbucks and Greggs provided the lowest average salt levels in the out–of–home sector. 

Based on the findings, Action on Salt & Sugar is calling on the UK government to enforce stricter rules on salt in sandwiches. 

'More than 20 years after the first set of salt reduction targets were introduced, it’s frankly unacceptable that some companies continue to sell sandwiches that exceed an adult’s daily limit in one go,' Ms Pombo said. 

'Voluntary action has been allowed to drift for too long, and the result is a food environment that continues to put public health at risk. 

'The Government must now step in with tough, mandatory measures, because leaving this to industry goodwill has clearly failed.'

While salt reduction is one of the quickest, cheapest and most effective ways to improve public health, progress has 'stalled', according to Dr Pauline Swift, Consultant Nephrologist and Chair of Action on Salt & Sugar. 

'Too much salt drives up blood pressure, one of the biggest causes of preventable strokes, heart disease and kidney disease,' she explained. 

'People should not be exposed to a hidden health risk every time they buy lunch.

'Ministers need to stop relying on voluntary promises and start taking prevention more seriously.'

The news comes shortly after the group revealed the popular supermarket soups that contain dangerous amounts of salt. 

The team analysed more than 480 varieties sold in supermarkets across the UK – and found that nearly a quarter exceed recommended levels. 

Topping the list is Soup Head's Tom Yum Soup, which contains a whopping 3.03g of salt in a 300g pack.