TRADING Standards bosses are being forced to scale back on undercover spot-checks at York's shops, because they risk being left open to legal challenge.

York's Trading Standards team has for many years used underage volunteers to test whether shops are selling goods such as tobacco, alcohol, fireworks, knives and spray paints to underage customers.

Matt Boxall, York Trading Standards manager, has warned that such undercover work may only be allowed for tobacco or alcohol.

City officials carried out no such checks in relation to fireworks and knives last year.

Random checks for the other products, and for sun bed sessions, would not be outright unlawful, he said, but they could be open to a challenge under human rights legislation.

His warning follows changes in 2012 to the Regulation of Investigatory Powers Act (RIPA), governing how public authorities can carry out surveillance work and investigations.