The era of the domination of North Sea gas comes to an end tonight when a tanker berths at National Grid's new £130 million terminal on the Isle of Grain, Kent. The ship, above, is carrying 31 million cubic metres of liquid natural gas from Algeria - enough to supply 47,000 homes for a year. As North Sea supplies start to dwindle, Britain will depend more on dearer LNG from areas such as Egypt and Algeria.