Sainsbury’s shares have risen by as much as 20% amid speculation that the Qatari Investment Authority was planning a renewed offer for the grocer.

Rumours have been circulating the City that QIA, which currently owns a 26% stake in Sainsbury’s, was interesting in renewing a bid after pulling away from an offer of £10.5bn for the company two years ago.

According to Reuters, traders reported rumours of a possible offer at 420p a share and that former Barclays banker Roger Jenkins was broking a deal.

Sainsbury’s declined to comment.