Abellio is to sell 40% of its Greater Anglia rail franchise to Japanese company Mitsui, saying the joint venture will lead to "significant improvements" for passengers.
Abellio said the announcement fulfils its objective of finding a suitable partner to run Greater Anglia in a 60:40 joint venture.
Dominic Booth, managing director of Abellio, said:
Not everyone is happy through. Mick Cash from the RMT Union said
Abellio won the Greater Anglia franchise again last August, having first operated it from February 2012.