Welsh Water has bought 28 West, a speculative office building at Newport’s premier out of city business location, Celtic Springs Business Park, and is set to move 400 workers in at the start of the year.

The Welsh Water employees housed at the Grade A office block, on three floors and in six wings will be responsible for delivering a £1.5bn investment over five years by the firm.

The £9m building, which has lain empty on the £100m business park since it was completed in 2008 offers a total of 35,000 sq ft of space. It was sold for an undisclosed sum.

A spokesman for the new owners said: "We have purchased office space at Celtic Springs in Newport which will accommodate around 400 employees. The new office will house our teams which will be responsible for the planning and delivery of the £1.5bn we will be investing between 2015-2020.

"Our investment during this period will deliver further improvements for customers and protect the environment."

He said: "It is anticipated that we will begin occupying the building from early in the new year."

The spokesman said the 400 employees would not be made up of new jobs but would be a mixture of existing Welsh Water staff and contractors working to deliver the investment programme.

The building, 28 West, was previously known as CS3000. It was built as a joint venture between AWG Property Ltd and Robert Hitchins.

Over the years various private and public organisations have shown interest in the building, which is adjacent and almost identical to the building occupied by Wales and West Utilities. Also in the vicinity are EADS and HM Prison Service.

When the building was constructed, planning permission for another office block, on four floors and offering 1,400 sq ft of space was granted. The headquarters project, for the central plain area of the business park, was never progressed.

Now the developers have turned their thoughts to building houses on this remaining site, which is close to Junction 28 of the M4.

Also housed at or near Celtic Springs Business Park are a number of other businesses, a children's nursery, hotel, restaurant and a retail quarter, which includes a hairdressers, private tutor and a Greggs.