Tedderboy - Pontius Navigator and SwitchMonkey have hit on the correct elements utilised by Manning (and Cranwell) to recruit from outside of the Commonwealth. There was a former USAF exchange officer aircrew commissioned into the RAF in 2006 (and he is still serving) on the basis that he was in the UK, a current instructor on an RAF type and was "able to obtain" UK citizenship. Manning was willing to waive the standard nationality requirements, as he filled an aircrew position that was in very short supply and on the condition he commence the naturalisation process. It's worth noting he (rightly) had to take a reduction in rank and work his way back up with everyone else. Things might have changed significantly since 2006, including UK visa and immigration rules. Even then, it won't be as straightforward in the instance, as the chap in this case appears to not be in the UK.