Prime Minister David Cameron insists Britain can remain a world power despite the emergence of new economic titans like China. But he says the country must get its financial house in order if it is to continue to carry weight in the world. In a major foreign policy speech on Monday, Mr. Cameron will reject the idea that the rise of new economic powers means British decline. In extracts released by his office, Mr. Cameron says Britain has a powerful combination of assets, including the worlds fourth-largest military budget, a vibrant and tolerant society and an outward-looking economy. Six months after he took office, Mr. Cameron says reducing national debt is a key priority, because economic weakness at home translates into political weakness abroad.