The Queen has asked if customers can fool modern technology to get away with cheaper shopping.

While being given a demonstration of a self-service supermarket till and its weighing scale system on Wednesday, the Queen asked: “You can’t cheat then?”

She was also shown a new shopping app, which she called “an interesting tool”.

The Queen made the comments during a trip to a pop-up exhibition in Covent Garden, central London, which replicated elements from one of Sainsbury’s original stores to mark the chain’s 150th anniversary.

Queen visits Sainsbury’s anniversary model.
The Queen asked about cheating the self-service checkouts (Jeremy Selwyn/Evening Standard/PA)

The supermarket opened its original store in Drury Lane in 1869, selling butter, milk, and cheese.

During her visit, the Queen also got the opportunity to see an original ration book from the Second World War, and reflected on her own experiences of food shortages.

She said: “As a Sunday treat we had some sweeties, but we were lucky we had a farm.”

Queen visits Sainsbury’s anniversary model.
The Queen was not impressed with herring paste, describing it as “ghastly” (Jeremy Selwyn/Evening Standard/PA)

There was also a demonstration of a shopping basket from the 1950s, containing a herring paste that the Queen labelled as “ghastly”.

When the porridge and oranges of six decades ago were contrasted the avocados and ready meals of 2019, she remarked “tastes have changed”.

The Queen met 33 members of Sainsbury’s staff during her visit, before unveiling a plaque and cutting a cake to commemorate the milestone birthday.

Queen visits Sainsbury’s anniversary model
A replica of one of the original Sainsbury’s stores was created to mark the 150th anniversary of the supermarket (Dominic Lipinski/PA)

They included Damien Corcoran, who showed the Queen the stores’ modern technologies, including the till.

A former Army officer, Mr Corcoran said it was a great honour “to have held the Queen’s commission and then to have met her in person”.

Queen visits Sainsbury’s anniversary model
The Queen chatted with Lord Sainsbury during the visit (Dominic Lipinski/PA)

Lord John Sainsbury, life president and former chief executive of the company, greeted the Queen and called her visit “very flattering”.

He said: “I’m proud to say that what the company has contributed over the years has made it worthy of it.

“Of course, it’s a great compliment.”