British outsourcing firm Capita has signed a deal with Telefonica UK (O2) to run its customer management services for ten years.

The move comes after reaching an agreement with unions over terms for workers to be transferred to the firm.

As per the deal, what is said to be the biggest ever in the UK, about 2,700 advisers based at four locations in the UK have been moved to Capita’s management.

The UK Communication Workers Union voted for strike action in June 2013, but an agreement was then reached with Telefonica UK on workers’ conditions, which also includes a two-year job assurance.

O2 also launched a voluntary redundancy programme to cut around 1,000 of its employees at Leeds, Glasgow, Preston Brook and Bury offices, following the announcement that Capita was the preferred bidder on 21 May 2013.

Recently, indebted O2 Ireland mobile business was acquired by Hutchison Whampoa under a €780m deal and is planned to be merged with Hutchison’s Irish mobile operator, Three.

The combined business plant to develop a modern network that includes 4G/LTE in the following years.