The wholesale price of gas goes up and the retail price goes up. The wholesale price goes down and the retail price stays the same.
British Gas have announced a price rise of 7% today and Scottish and Southern have announced a rise of 9%. http://www.bbc.co.uk/news/business-11743778
Here's a link to an article on the Consumer Focus web-site with a nice graph of wholesale/retail prices since 2007 http://www.consumerfocus.org.uk/news/consumer-focus-response-to-sse-gas-price-increase