More surprisingly, the findings revealed that the generosity of several of the 'Big Six' energy suppliers' social tariffs are actually more expensive than the sum of their lowest priced energy offers.
The watchdog's social policy analyst, Richard Bates, said: "Customers on social tariffs must be assured that they are on a company's lowest rate regardless of who their supplier is.
"Even on the assumption that suppliers will fulfil their commitments, it is clear that the assistance offered will fall well short of the response needed to mitigate the impact of high energy prices on Britain's most vulnerable households."
Allan Asher, the chief executive of energywatch, has also recently urged the government to act on the rising price of household energy in the UK.
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