In October 2006, BT confirmed that it would be investing 75% of its total capital spending, put at £10 billion over five years, in its new Internet Protocol (IP) based 21st century network (21CN). Annual savings of £1 billion per annum were expected when the transition to the new network was to have been completed in 2010, with over 50% of its customers to have been transferred by 2008. That month the first customers on to 21CN was successfully tested at Adastral Park in Suffolk.