Boris Johnson is set to bring back pounds and ounces in shops to mark the Queen's Platinum Jubilee.
Ministers are preparing to consult on how to further incorporate imperial measurements in Britain after Brexit, with the prime minister reportedly keen to announce the move on Friday to coincide with the Jubilee.
But the move has faced criticism from the Conservative backbenches, with Alicia Kearns – one of at least 20 Tory MPs to declare they have lost confidence in the prime minister over his handling of rule-breaking parties in No 10 during the coronavirus lockdown – calling the idea "a nonsense."
Ms Kearns, MP for Rutland and Melton, tweeted that “not one constituent, ever, has asked for this."
She added: “This isn’t a Brexit freedom. It’s a nonsense.”
The Sunday Mirror said Downing Street hopes the move could shore up support in Leave-voting areas after Conservative polling took a hit Partygate revelations.
The EU weights and measures directive came into force in 2000, with traders legally required to use metric units for sale-by-weight or the measure of fresh produce.
It remains legal to price goods in pounds and ounces but they have to be displayed alongside the price in grams and kilogrammes.
In the metric system, 1,000 grams are equivalent to one kilogram, whereas under the imperial system there are 14 pounds in a stone and 16 ounces in a pound.
For liquids, there are 20 fluid ounces in a pint and 160 fluid ounces in a gallon, as opposed to 1,000 millilitres in a litre under the metric system.
It is understood there will not be a move away from metric units but the consultation will look at where it makes sense to incorporate or switch to imperial measurements such as feet and yards, and pints and gallons, with traders likely to be free to choose which they use.
It is part of a wider effort in Whitehall to review what EU regulations remain on the UK’s statute books after Brexit.
Before a looser interpretation of the EU’s directive was introduced, some shop owners were prosecuted for failing to adhere to the Brussels stipulations, becoming known in the press as the “metric martyrs."
Brandon Lewis, the Northern Ireland Secretary, said on Sunday that while the policy was “light-hearted” and a “smaller” freedom provided by Brexit, there were people who “want to go back” to using imperial weights.
He added it would allow the likes of greengrocers and pub landlords to run their businesses as they see fit following the UK’s exit from the EU.
He told Sky News’s Sophy Ridge On Sunday programme: “This gives people and businesses the freedom.
“There are sectors out there – I know people out there in my constituency, the market traders and vegetable traders as well as some of the pubs – which will be pleased to be able to go back to those imperial measurements.
“We’re just saying you now have a choice, and now we’ve left the EU we can do that.
“Yes, it is one of the smaller things we can do since we left the EU, there are other bigger things we can do and want to do, but it is an indication we now have the freedom to make these decisions ourselves.”
The UK currently uses a mix of imperial and metric, with speed limits in miles per hour rather than kilometres, and milk and beer bought in pints.
Food packaging in supermarkets is mainly labelled in grams, while most soft drinks and other liquids on shop shelves are sold in litres.