According to the Daily Express, these moves by major energy firms may be why energy customers in Britain have been hit by higher bills at the start of this year.
Speaking to the newspaper, energywatch's campaigns director Adam Scorer said: "The big European energy companies treat Britain like a treasure island.
"Ever since the British market became more exposed to continental prices that has been happening."
Mr Scorer's comments come after he stated that recent figures from Ofgem on the number of people in the UK switching energy deals were "good news".
The research by the energy regulator found that 5.1 million customers have changed gas and electricity providers or tariffs in the past 12 months.
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