A pub chain boasting more than 300 outlets has banned customers from talking on their mobile phones while on the premises.

In Samuel Smith's pubs, a chain originating from Tadcaster, North Yorkshire, customers wishing to make a phone call will have to go outside, the same as smokers.

Photographs of a memo telling managers to enforce this rule, allegedly sent by pub boss Humphrey Smith, have been published by the Manchester Evening News.

It dictates that customers wishing to check their phones must go outside "in the same way as is required with smoking".

According to the memo, the ban also applies to laptops and tablets, and says that customers are also not allowed to "receive transmitted pictures of sport or download music apps".

"The brewery's policy is that our pubs are for social conversation person to person," it concluded.

The 73-year-old proprietor is said to regularly go into his pubs incognito to check his staff are enforcing the rules.

He reportedly makes great efforts to get his customers to maintain the art of pub conversation, and keep standards that would make the original Samuel Smith proud when he founded the brewery in 1758.

London landlord Oisin Rogers, who runs The Guinea Grill in Mayfair, said Mr Smith was "going all Willie Wonka again" with the latest ban.