ONE-third of fish and chip shops tested in Glasgow were found to be replacing haddock with cheaper cuts of fish.

The investigation has led to calls from consumer rights ­organisation Which? for better regulatory investigation.

As part of a Stop Food Fraud campaign, Which? tested 15 samples of fish labelled as haddock bought from random fish and chip shops in Glasgow. Five of the 15 samples tested were found to be whiting, which is similar to haddock but usually cheaper.

Which? is to pass on the details of the five chip shops to Glasgow City Council. The results come just five months after testing lamb takeaways south of the border found 40 per cent had been contaminated with other meats, with some containing no lamb at all.

With half (49 per cent) of consumers saying they are not confident that the food they buy from takeaways is correctly described and contains the ingredients stated, Which? says it is campaigning for food fraud to be a greater priority.

It said the new food agency, Food Standards Scotland (FSS), must have strong powers and be prepared to tackle food crime.

"Consumers need to be confident in the food they are buying and we want the FSS to put consumers at the heart of their work," said Which? The new body, to replace the Food Standards Agency in Scotland, would have a wider scope, including greater powers to tackle diet and nutritional health in addition to regulating food safety.

The new agency would have the power to sanction anyone breaking food laws.

The Food (Scotland) Bill, which would establish FSS, is currently being debated at Holyrood.

Which? has passed its findings to Glasgow City Council, the Food Standards Agency in Scotland, Trading Standards Scotland and members of the Scottish Parliament's Health and Sport Committee who are considering the proposals for a new food standards body.

Head of Which? public affairs for Scotland, Gordon MacRae, said: "It's unacceptable that people are being misled, and that the food they have ordered is not what they're told it is. Consumers need to feel ­confident in the food they buy. It's in the interests of responsible food businesses, as well as consumers, to make sure there are effective controls in place and a zero tolerance approach to food crime.

"The creation of the new food agency, Food Standards ­Scotland, provides an ideal ­opportunity to ensure that there is a tougher approach to food fraud."