I don't even work for Nats yet... but what is being talked about seems to be very similar to what is happening to my Police Pension.
When I joined the pension you were offered was: 1/60 per year (2/60th for year 21-30) ie 40/60ths after *30* years, for 11% contribution (you can reduce pension to 1/2 and take a nice lump sum nearly 3 times your basic salary when you leave).
From 1st April 2006 (or 5th?) anyone who joined joined the NPPS (NEW Police Pension Scheme) - 1/70th per year, ie 35/70ths after *35* years + 1.5 times your basic salary as a lump sum, for 9.5% contribution (you can UP your pension by REDUCING your lump sum).
Everything goes along swimmingly for 4-5 months, then the charm offensive starts... They publish ALL the good points about the new pension scheme, ALL the bad points about the old one, and indicate how much money you can save by transferring etc etc... They have just recently sent out a pack "selling" the new pension scheme, with a form to sign to transfer over... About 1% will. However they have now reduced the cost of the police pension quite significantly.
This is very similar to what many blue chip companies have done, closed their old "gold-plated" pension (final salary, often no contributory) and changed it for a money purchase scheme (everyone has their own pot). I can only think of one company that has closed it's current pension scheme to existing employees, even then what they have earned upto that point is safe. They just are forced onto the new scheme from that point onwards - not nice I agree, but unlikely.
I just hope the change is not for a little while, to allow me to get in quick on the old scheme!
Cheers
James.