Huh? There are flights arriving daily from India, India was where the strain was first detected months ago, and in some parts of India it is the predominant strain. Neither of the two mutations that strain has acquired match the mutation that the B117 (which now dominates the UK and in process of dominating US) strain has.

Multiple trails of evidence pointing to it's emergence in India, and right now the UK is not restricting travel from India so the most likely scenario is that it arrived in the UK from someone who traveled to India or another country where that strain is spreading.