Centrica said "cooler weather" in 2012 saw domestic gas consumption increase by 12% following a warm 2011.
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The company posted a 63.5% plunge in bottom line pre-tax profits to £176.4 million on a comparable 52-week basis.
Through the day, most of the cloud should break up to leave fine conditions for many with spells of sunshine.
The Eiffel Tower in Paris was plunged into darkness, with the Burj Khalifa in Dubia emblazoned with the Union Jack.