“Only the US, Russia, China and UK have bigger arsenals.”
I think the UK only has a couple of hundred; China, 300 or so.
China ‘has up to 3,000 nuclear weapons hidden in tunnels’, three-year study of secret documents reveals
http://www.dailymail.co.uk/news/article-2067984/Chinas-nuclear-arsenal-seven-times-bigger-previously-thought-students-discover-year-study-secret-documents.html#ixzz28RZgxngE