No offence Jet A1, but that's a pretty lazy reply.
"Candidates must be UK residents aged over 20 and under 32 at entry to training, with the unrestricted right to live and work in the UK. You must also hold an unrestrivted world-wide password and have the ability to obtain a UK CAA Class I Medical Certificate".
Nationals from other countries can certainly apply, you simply must have the right to live and work indefinitely within the United Kingdon. A Right of Abode certainly grants you this priviledge. Some visa types, such as an ancestory visa (commonly called a Grandfather visa) may also, but applicants need to check on this last point.