This is really interesting and DARPA had better check it out.
The distance between Beijing and London is 5,064 miles and that means that the PRC has a missile that can travel at an average speed of 10,128 mph. That means that it is going to be travelling well in excess of 15,000 mph (MACH 20) at impact.
PS - "The Mirror" isn't noted for its accuracy BUT it IS noted for scandal-mongering.