British Megayachts

We all know about Roman Abromovich and his fleet of yachts and that he is resident in London. But after Roman, which Briton owns the largest yacht yacht? Would that be the Barclays after their purchase of Katana (now Enigma)?

Also, the British retail tycoon Phillip Green has a yacht moored in Monaco - can anybody tell me what it's called and have any details / pictures of it?