The company was once a constituent of the FTSE 100 Index, but subsequently went into administration, and then became a subsidiary of Cable & Wireless, in turn acquired by Vodafone.

[1] Energis acquired a number of companies in the United Kingdom and Europe, including Planet Online,[2] ISION AG[3] and others.

In November 2002 the Ision parts of the energis group were sold onto NDO with the remainder, mostly made up of Planet Online continued asEnergis Communications Ltd until August 2005.

[6] The bid was accepted by a binding majority of Energis debt holders, and the company became part of Cable & Wireless on 11 November 2005.

[7] In its final form, Energis provided a number of services based around its core platforms of ISP, transmission, IP networking (Energis had a Nortel SDH network with Internet access provided via Cisco routers using MPLS technology), contact centre solutions and voice (traditional switched telephony).