Cossack - you can't transfer a foreign pension into the Nav Canada scheme, apparently due to some old rule from the days of Transport Canada.
As for NATS (actually the CAA pension scheme administrators) deciding where one can put one's own money, how ludicrous is that?
The idea of getting a Sterling pension in Canada sounds okay in theory, but my UK pension as it stands will give me a whole £7,000 p.a. at age 60, and that's before tax for which there is no shelter if it didn't start out in an RRSP!
You know those annual statements that say you'll £xx,xxx at retirement? Those assume you'll continue working for NATS at your current salary until retirement age. Look at what you'll actually get, and then factor in generally higher economic growth in Canada, and it looks like a no-brainer to me!