Pressure group Consensus Action on Salt and Health (CASH) has called for a boycott of breads with high salt levels as part of its Salt Awareness Week campaign, which runs until February 4.

It says that while many bakery products now contain significantly less salt than a few years ago, salt levels in others are still too high.

Its research found that a white crusty farmhouse loaf bought from Marks & Spencer in September 2004 contained 1.75g of salt per 100g, whereas the same product bought at the end of 2006 contained around half this amount of 0.9g salt per 100g.

Many other loaves now contain around 0.8-1g of salt per 100g. However, some bread still contains as much as 1.5g of salt per 100g.

CASH has urged consumers to avoid buying Tesco’s Stayfresh Medium Sliced Wholemeal bread (1.5g salt per 100g) and choose Sainsbury’s Stay Fresher For Longer Medium Sliced Wholemeal bread instead, as it contains much less salt (0.9g per 100g).

Indeed, any bread that contains more than 1.25g of salt per 100g should be boycotted, as lower salt alternatives exist, according to CASH.

"The UK is leading the world on salt reduction - many of our food manufacturers should be congratulated on the effort they have made to reduce the amount of salt they add to our foods," said Professor Graham MacGregor, chairman of CASH. "This proves that lower salt versions can be developed."

In its latest survey, CASH revisited 127 products it had previously ’named and shamed’ to see how their salt contents had changed.

It said products still found to have a high salt content included Sainsbury’s and Tesco Crumpets, which contain 2g of salt per 100g.