UK billions aren't always the same as US billions. When billions are used in the UK, they often mean what the Americans would call trillions. It's important to get clarification on which billion they're actually using in figures because they still use both!
"There is also a historical difference between billions, trillions and so forth. Americans use billion to mean one thousand million (1,000,000,000), whereas in the UK, until the latter part of the 20th century, it was used to mean one million million (1,000,000,000,000). In 1974 the British prime minister, Harold Wilson, told the House of Commons that UK government statistics would now use the short scale; followed by the Chancellor, Denis Healey, in 1975, that the treasury would now adopt the US billion version."
http://en.wikipedia.org/wiki/Comparison_of_American_and_British_English#...