The board of the rail and bus operator has reached an agreement with a consortium made up of Australian bus operator Kinetic and Spanish transport infrastructure company Globalvia to buy all of the shares in the company at 1,500 pence each - valuing the firm at £647.7m.
But fellow Australian transport firm Kelsian - which has also made an initial takeover approach - has released a statement urging Go-Ahead shareholders not to accept any bid as it finalises its potential offer.
The takeover interest comes after a challenging period for Go-Ahead, in which it received a £23.5m fine over a breach of a rail franchise around London.
