Morrisons’ biggest shareholder has said it will not support the £6.3 billion private equity-backed takeover deal for the supermarket chain in a heavy blow to the retailer’s board.

It comes around three weeks after the UK’s fourth largest grocer agreed to a takeover by a consortium led by US private equity firm Fortress.

Silchester International, which owns a 15.14% stake in Morrisons, said on Tuesday that it is “not inclined to support” the agreed deal.

The current offer is priced at 252p per share, as well as a conditional special dividend at 2p per share for investors.

Morrisons shareholders are currently due to vote on the offer, which was supported by the firm’s board of directors, at a general meeting on August 16.

The retailer agreed to the takeover move days after it rebuffed an initial £5.5 billion approach from rival private equity firm Clayton, Dubilier & Rice (CD&R).

UK takeover regulators have given CD&R a deadline of August 9 to either place their own firm bid for the chain or walk away.

Fellow institutional investor Apollo had reportedly been interested in an offer for Morrisons but confirmed last week that it was in talks to join forces with the agreed Fortress-backed takeover offer.

Silchester told other shareholders that believes the process regarding the potential takeover is also “disadvantageous to public shareholders generally”.

The firm called on Morrisons’ board to “allow more time to respond to other parties who might offer better value to Morrison’s public shareholders”.

It added that it believes “there is little in the recommended offer that could not be achieved” by Morrisons under its current ownership as a publicly-listed business.