As a result, the number of shipments arriving at an American terminal belonging to BG, a big gas firm, fell from 48 in the second quarter of the year to one in the fourth.

ECONOMIST: Liquefied natural gas

On its website, petrol company Shell said prices can vary from region to region due to "factors such as distance from the refinery or distribution terminal to the petrol station and the number of customers in the region".

BBC: Bedford mayor calls for 'boycott' of expensive petrol

The airport is due to complete the reconstruction of Terminal 2 in 2014, which will increase the number of passengers it can handle, but not the number of flights.

BBC: Heathrow: 2012 'busiest year on record'