Many family restaurant meals 'contain more than twice as much salt as a child should have in a day'

Researchers also found that a three-course meal could contain more than 15g of salt, when adults are warned not to have more than 6g daily.

Doctors have long warned that too much salt can affect the body's blood pressure and contribute to a stroke or a heart attack.

The new study, by the group Consensus Action on Salt and Health (CASH) and Trading Standards officers across the country, measured the salt content of 96 meals from 16 popular chains.

It found that almost three in four main courses contained 3g of salt, the daily limit for a six-year-old, or more.

More than a third of the restaurants served a main dish which contained 6g of salt or more.