Asda is trialling a new style of checkout which could banish the ‘This till is closing’ sign forever.

The supermarket has been testing a ‘hybrid’ till, which switches from a checkout operated by a member of staff to a self-scan till at a moment’s notice.

Four hybrid checkouts have been trialled in Asda’s Keighley superstore. A spokeswoman for Asda said the trial had gone “very well”, and that it would be rolling out the tills to another four superstores later on this summer.

The biggest advantage of the hybrid tills, which can be used by customers with trolleys as well as baskets, is that they will enable Asda to have checkouts that are always open.

“During busy periods, the checkout will be manned by a colleague, while during quieter periods the checkout will be open in self-serve mode - so we really will be open all hours,” she said.

“So far it’s proving effective in reducing queues and improving service levels during extra-busy times in the store. The concept is to provide customers with a checkout that is always available.”

In theory, if every checkout in an Asda store was a hybrid then every single one could remain open during opening hours, regardless of how many till operators were on duty.

That could slash queuing times, which are regularly voted by customers as the biggest irritation of supermarket shopping. It would also give Asda an advantage when it comes to winning the Grocer 33 award for service.

A fortnight ago, The Grocer’s mystery shopper queued for more than three minutes in an Asda store that had 13 of 34 tills open. But the week before that, Asda had 29 tills of 31 open and our shopper queued for just 30 seconds. Last year, Asda shoppers queued for an average of two minutes 33 seconds.

Self-scan tills appeared in the UK in 2002 and were first trialled by Asda and other supermarkets in 2003. They quickly became notorious for frustrating shoppers by announcing the presence of unexpected items in the bagging area.

Meanwhile, a recent survey of 5,000 shoppers by watchmywallet.co.uk revealed one in three self-scan shoppers is tempted to shoplift. Chef Antony Worrall Thompson was famously arrested in January for bagging items without scanning.

And self-scan tills also faced accusations from unions who claimed supermarkets were rolling them out to cut staff numbers rather than for customer convenience.

However, Asda said the customer reaction to the hybrid tills had been “very positive” and that a “surprisingly high” number of trolley shoppers had opted for the new self-scan tills.