LONDON (Reuters) - The British government said on Tuesday it had awarded Boeing <BA.N> a five-year contract worth 420 million pounds ($644.91 million) to provide in-service support to its fleet of Chinook military helicopters.

"The Chinook support contract represents significant value for money for what is a very capable and versatile support helicopter, protecting UK interests at home and abroad," British Prime Minister David Cameron said in a statement.

"This will sustain 450 jobs and save the taxpayer over 150 million pounds," he said, adding that BAE Systems <BAES.L> and Magma Structures had been chosen as the preferred bidders to occupy the Portsmouth ship hall facilities in southern England.

($1 = 0.6513 pounds)

(Reporting by Andrew Osborn; Editing by Susan Thomas)