Three quarters of supermarket-bought bread contains as much salt in a slice as a packet of ready salted crisps, health campaigners have warned.

Action on Salt surveyed 242 pre-packaged loaves of sliced bread from 28 firms sold at 10 of the UK’s largest supermarkets, and found three in four contained as much salt or more per slice than the 0.34g found in a packet of ready salted crisps.

The saltiest loaf was Hovis White with Starter Dough, containing 1.48g of salt per 100g of bread – nearly three times the amount of the least saltiest Waitrose Rye and Wheat Dark Sourdough, with 0.51g of salt per 100g, the charity found.

A consumer eating two slices of Hovis Soft White Extra Thick bread would be consuming a fifth of their maximum recommended daily salt intake, Action on Salt said.

While the majority of loaves fell below the 2024 maximum salt target set by the Department of Health and Social Care in 2020, Action on Salt said the large variations suggested that the targets were “far too lenient”, with scope for further reductions.

Too much salt is known to increase the risk of high blood pressure, which is linked to heart disease and stroke. High blood pressure affects around a third of adults in England.

Action on Salt is now urging Prime Minister Rishi Sunak to follow other countries around the world by setting mandatory salt reduction targets.

It said even small reductions in the salt content of bread would have a significant impact on public health.

Previous research on bread suggested salt content had been reduced by 8% since 2011, with some notable reductions for particular loaves such as Vogel’s Original Mixed Grain, Vogel’s Soya & Linseed and Schneider Brot Organic Sunflower Seed Bread.

However, some appeared to have increased in salt since 2011, including Sainsbury’s Medium Wholemeal, up 19%, the charity said.

Graham MacGregor, professor of cardiovascular medicine at Queen Mary University of London and Action on Salt chairman, said: “Reducing salt is the most cost-effective measure to lower blood pressure and reduce the number of people dying and suffering from strokes and heart disease.

“It’s therefore a disgrace that food companies continue to fill our food with so much unnecessary salt, as shown here in bread. For too long the food industry have been in charge of public health, at our expense; it’s time for the Government to stop letting people die needlessly.”

Hovis said: “Over the last 20 years, Hovis has been actively reducing the levels of salt in its products, with the data provided by Action on Salt confirming this notable reduction over time.

“The vast majority of our range is fully compliant with current salt targets.

“The three Hovis products that Action on Salt have highlighted as exceeding the voluntary salt targets are Cobs, which are part of our premium Hovis 1886 artisanal-inspired range, developed to deliver exceptional taste and variety for those special occasions that they are bought for.

“All our product recipes are continually reviewed in light of evolving guidelines and will continue to be carefully crafted to the highest standards, as they have been for almost 140 years, being enjoyed in moderation as part of a balanced diet.”

A Sainsbury’s spokeswoman said: “We are committed to helping our customers access healthy and sustainable diets.

“100% of our sliced bread products meet the 2024 Public Health England maximum salt target and we regularly review ranges in line with Government guidance.”