Britain’s attempt to ramp up mass coronavirus testing has been dealt a blow after key components ordered from overseas were discovered to be contaminated with coronavirus, the Telegraph can disclose. Laboratories across the country were on Monday warned to expect a delay after traces of the virus were detected in parts due for delivery in the coming days. It comes as ministers and public health chiefs face growing questions over why Britain’s testing capacity appears to be lagging far behind other major nations including the US and South Korea. To accelerate production, the government has enlisted private firms to help produce thousands of kits in the hope that mass testing will be available to the public within weeks....