If you think this is worrying look at table ET1.1 at the UK Department of Trade and Industry statistics. There they have figures for July and August 2005. At 1 million  tonne oil equivalent = 11.63 TWh, the figures are:-
July   71.1 TWh
August 54.7 TWh
This means production in August 2005 was 23% down on August 2004. The UK has no facilities to import liquid natural gas and only a small pipeline across the English Channel to mainland Europe that is already working at full capacity.
Thanks Nick!  Here's an updated graph:

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