Stadium House (Ty Stadiwm) is owned by the BT Group. Located next to the Millennium Stadium in Cardiff, it was designed by the Percy Thomas Partnership. Work started on the building in March 1974. When it was completed, in 1976, it was the second tallest building in Cardiff. The addition of a stainless steel spire, in 2002, made it technically the tallest (roof height is not included in 'official' classifications).
L. Moore, RCAHMW, 3rd February 2012