Had to switch my energy tariffs today with British Gas as, although the exisiting ones go to the end of the month, the email from them said I had to do it by today. Gas price slightly higher, electricity price massive increase - overall just over 13% price increase in the last 2 years.
Posting this as a warning to anyone on a fixed rate tariff who only use electricity as when you come to renew you could be in for a shock (a 27% increase in my case) 
As my smart meters are of the first generation, switching to another supplier is messy and time consuming. Second generation smart meters are supposed to be more able to be switched between energy providers.