McKillen won the right to appeal against an earlier High Court decision regarding the battle between the two parties for ultimate control of the company, after previously losing a lengthy trial - costing around £20m - against Sir David and Sir Frederick Barclay.
It is believed that McKillen will question the High Court judge's interpretation of the shareholders agreement signed by investors in Coroin, the company set up by financier Derek Quinlan to buy the three hotels, along with the Savoy in 2004. The Savoy was sold the following year to Prince Alwaleed bin Talal of Saudi Arabia.
McKillen believes that the shareholders agreement was broken when Quinlan transferred his control of the company to the Barclay brothers, who already own London's Ritz hotel. He is also expected to argue that pre-emption rights to allow existing shareholder to buy out others had been triggered because security held by a number of Quinlan's creditors had been triggered for non-payment of debts.
The Barclay brothers currently have a 64% stake in the business, with Mckillen holding the remaining 36%.
The appeal is expected to take around two months to be heard.
By Janet Harmer
E-mail your comments to Janet Harmer here.
Looking for a new job? Find your next job here with Catererandhotelkeeper.com jobs