Delta Two, the investment vehicle of the Qatari royal family, has increased its stake in Sainsbury’s to more than 25%, it was revealed this morning.

The stake is edging closer to the 29% threshold where an investor must clarify its position on a takeover of the supermarket.

Delta Two, run by ex-Rotch Property Group chief executive Paul Taylor, has made an investment of £732m - buying 123m Sainsbury’s shares at 595p a share.

Rotch founder Robert Tchenguiz already owns a 5% stake in the grocery retailer and had been pushing for Sainsbury’s to exploit its £6.8bn property portfolio by splitting the properties off from the operating company.

The news of the stake building follows months of stalking by private equity consortiums. Sainsbury’s board rejected a bid by the CVC-led private equity consortium in April, which was believed to have been made at 582p.

Delta Two is the investment vehicle controlled by Sheikh Hamad Bin Jassim Bin Jaber Al Thani with investors including the Qatari Investment Authority, Qatari Diar Real Estate Investment Company and Standard Capital Limited.