TalkTalk has appointed Gary Steen as its new chief technology officer, replacing Clive Dorsman who retires this summer after 17 years at the company.

Steen will move from his current role as chief development and delivery officer, and will lead the group's overall technology strategy, encompassing network build, IT operations and software development. His team makes up a quarter of the TalkTalk workforce.

Steen said: "It's an exciting time for TalkTalk. We're Britain's fastest growing TV service, TalkTalk Business is one of the fastest growing B2B telecom operators in the UK and we have a great strategic advantage in our wholly-owned Next Generation Network.

"Demand for data is exploding and this, coupled with the exciting new innovation projects we have in the pipeline, means it's a fantastic time to be taking on this role."

Steen has experience designing and implementing systems for the telecommunications market, having worked with companies including AOL, Vodafone, BT, O2 and Carphone Warehouse, before joining TalkTalk in 2012. He will report to TalkTalk CEO Dido Harding.

Chief executive Harding said: "We're delighted to appoint Gary as CTO. His wealth of expertise in technical innovation will strengthen our position even further."

Dorsman had joined TalkTalk in 1997 as managing director of technology, was chief networks officer from 2008, and took overall responsibility for IT as the CTO in April 2011 when CIO David Cooper left to join British Gas.

TalkTalk Business was named as a strategic supplier by 3% of this year's CIO 100.