Can't give you chapter and verse I'm afraid but that has been my understanding anyway.
I can fully understand why so many people feel cheated. I worry about the situation of my own children who are now in their 40s with very little short term job security or loyalty from employers, and little long term financial security.
One other side comment: to some extent these things reflect trade-offs. Prior to BA privatisation, I attended a number of IFALPA conferences where we were obviously mixing with senior pilots from other countries, and discussed pay and conditions. Because of being government owned and subject to prices and pay policies set by politicians, the Brits were pretty much the poor relations in terms of salaries especially compared to the equivalent US pilots, not to mention Air France, Lufthansa and some others.
Since we weren't allowed to have high salaries "the system" somehow found compensations, such as better working conditions and a much better pension scheme, though I didn't appreciate it at the time. I do know that my standard of living today is higher than some of my US friends who had much more money back in those days. But I do realise that was just our good fortune, not anything we can take credit for.