Britain's fastest supercomputer that could help answer some of science's biggest questions has been unveiled yesterday. With the power of 12,000 desktop PCs, the mammoth machine called HECToR is the country's fastest computer and one of the most powerful in Europe. It can make 63 million calculations each second, allowing scientists to conduct research into everything from climate change to new medicines. The purpose-built machine is housed in 60 wardrobe-sized cabinets in the University of Edinburgh's advanced computing centre near the Scottish capital. After years of development, Chancellor Alistair Darling is due to attend the official launch ceremony for the 113 million pound machine. "HECToR will enable us to do research that we simply could not do in any other way," said Jane Nicholson, of the Engineering and Physical Sciences Research Council, the public body which acts as the project's managing agent. "We want to push forward the boundaries of knowledge."