Billionaire investor Warren Buffett has beefed up his holding in Tesco by a further £500m.

His Berkshire Hathaway investment vehicle has increased its share in the UK’s largest supermarket from 3.21% to 5.08%.

The move by the investment legend comes as a confidence booster for Tesco, which last week reported a 2.3% fall in like-for-like sales over the key Christmas period. Those results caused its share price to tumble by more than 15%.

Tesco this week unveiled the latest phase of its ongoing bid to wrest back the momentum from rivals, a £5 off voucher scheme that Asda suggested had borrowed heavily from a similar scheme of its own last year.