As many as 71% of SSEs’ customers are still on standard variable tariffs (SVT).
British Gas ranked second from the bottom, with 67% of its customers still on SVTs, while the three companies with the smallest proportion of customers on the variable contracts are independent suppliers.
These were First Utility, with just above a fifth of customers on the expensive tariffs, as well as Ovo Energy and Co-Operative Energy, with 28% and 35% respectively.
Ofgem says SVTs are still around £300 more expensive than the cheapest deals currently available but added the number of customers on these tariffs is decreasing as a result of record switching rates this year.
The regulator’s safeguard tariff will mean from February, one million households will be protected from what it believes are the most overpriced deals.