SITEL is an American owned call centre provider with substantial operations around the world. In The UK, they were originally the MITRE Group which consisted of Merit Direct (Stratford-Upon-Avon) & Decisions Group (Kingston-Upon-Thames). In 2006, they were acquired by Client Logic but retained the stronger SITEL brand.
They operate call centres around the world including North America, Europe & offshore destinations in Asia. They have fallen from grace to some extent in The UK going from by far the largest provider to the 3rd largest.
SITEL are not an industry specific vendor and have clients in telecommunications, financial services, retail and utilities. They offer both customer service and outbound services and also have a small technical support offering.