Boris Johnson’s plans to bring back imperial measures will cost at least £2 million and baffle most shoppers, a watchdog has warned.
Liz Truss has been urged to dump post-Brexit promises to reinstate old measures such as pounds and ounces.
The much-ridiculed idea will cost millions of pounds to implement and will force traders to fork out on new measuring devices and inspectors to pay for extra training.
A poll by the Chartered Trading Standards Institute (CTSI) also found that only half of shoppers were “confident” they could use pounds, ounces and gallons – falling to 30 per cent of under-44s.
John Herriman, the organisation’s chief executive, said: “At a time when we are facing a cost of living crisis, we would question whether this measure is necessary.
“When many of us are thinking about pounds and pence, should we be distracted by discussions about pounds and ounces?”
A “national public education campaign” on TV, radio and online about long-forgotten imperial measures – possibly including school lessons – would probably add millions more to the bill, the CTSI says.
Graham Wynn, assistant director of business regulation at the British Retail Consortium, warned of the “unnecessary complexity for consumers” from the move.
“Currently, the indication of imperial measures is allowed alongside metric ones where that is helpful for customers,” Mr Wynn pointed out.
In June, the Asda boss and Conservative peer Stuart Rose called the plans “complete and utter nonsense”, saying: “We have got serious problems in the world and we’re now saying ‘let’s go backwards’.
“Does anybody in this country below the age of about 40 know how many ounces there are in a pound?”