A sales probe is taking place in Britain with the tactics of some energy suppliers coming under scrutiny.

While there are six large UK energy suppliers, only four are being investigated amid concerns that customers were misled through telephone sales.

Npower, Scottish Power, Scottish and Southern Energy, and EDF Energy now face questions over face-to-face and telephone sales of energy contracts, which have recently come under new rules.

Research in the UK has found that people generally only change suppliers after contact with salespeople.