Tesco will offer customers a same-day online grocery delivery service across the UK by the end of August.

The supermarket group launched same-day grocery delivery in London and the South East in 2014.

It is now extending the service to more than 300 stores across the UK, covering more than 99% of UK households.

As part of the service, customers can order by 1pm to have their shopping delivered from 7pm onwards and receive an unlimited number of items. The service is priced between £3 and £8.

Earlier this year Tesco extended its same-day Click+Collect service to 300 locations and said this made it the only retailer to offer both to customers nationally.

Tesco Online MD Adrian Letts said: “Customers tell us they like getting their shopping delivered quickly and conveniently, and with our same-day delivery service they can now order by lunch to get their shopping delivered for their evening meal.”

Same-day delivery is a seven-day service in London and the South East but will operate six days a week in the rest of the UK.

David Jinks, head of consumer research at Parcelhero, said: “Tesco has never held back in pushing new sales technologies, and it is no surprise it has beaten Amazon to the punch in enabling same-day deliveries to around 99% of UK households.

“[However] Amazon teamed up with Morrisons and has no supermarkets of its own to cannibalise sales from; but Tesco has more than 6,500 stores.

“Its huge number of stores are what enables Tesco to reach 99% of UK households; but longer term the growth in home deliveries must endanger some of its own stores, particularly large out-of-town supermarkets, as home deliveries wipe out the dreaded weekly groceries shop.”

Amazon has been increasing the coverage of its rival Fresh service steadily adding Hampshire postcodes earlier this year.