The agency landed the business after a final shootout against Harrison Troughton Wunderman, following a pitch conducted by the AAR.
Lida will develop integrated communications aimed at reversing a £5 million loss of revenues from voice services in 2004. It will create communications to target key decision-makers at medium-sized and large companies. Its first task will be a campaign to support a product launch to improve working from home.
The business was previously handled by Draft London, which did not repitch.
Clare Grant, the Telewest director of marketing, said: "We were very impressed by Lida, not only with its innovative ideas but also by the strength of the individuals making up the team and their entrepreneurial flair."
The company keeps its business DM separate from the main direct account.
The consumer DM business is held by Rapier and is unaffected by the appointment.