Abellio Greater Anglia is a train operating company in Britain owned by Abellio (a subsidiary of Nederlandse Spoorwegen) operating the Greater Anglia rail franchise. It provides the majority of commuter/regional services from its Central London terminus at London Liverpool Street to Essex, Suffolk, Norfolk and parts of Hertfordshire and Cambridgeshire as well as many regional services throughout the East of England. The service was branded 'Greater Anglia' until December 2013.
The company's suburban London services were transferred to TfL Rail, the precursor to Crossrail, on 31 May 2015, and the current Greater Anglia franchise will be replaced by a new East Anglia franchise on 16 October 2016.
More information on the Wikipedia page [1]. The website is [2].