During approx 91-93 NATS had a very large recruitment drive resulting in over 200 controllers per year being recruited, mainly in their early 20s. Even removing those who failed to validate, have left since etc., there still remain a large number of controllers, a large number of whom have left the DB scheme, now in their early 50s, and who may decide that, as they are able to access their pensions from age 55, retirement is a very real option. Granted the ‘new normal’ conditions may have changed this perception to some extent, but there remains a very high number of controllers at least theoretically able to retire in the next 3-7 years.