While I am sure that what they say about the new variant being more virulent is true, I am not convinced that it is the sole cause of rapid spread in London and the SE. They have known about the mutation since September and it is already elsewhere in the UK. Surely keeping the area in tier 2 when it was obvious more restrictions were warranted has a lot to do with it. Keeping London out of lockdown was a political decision and now that has come to bite them on the bum they are looking for excuses.