The McCloud judgement relates to those in public sector final salary defined benefit pensions in 2012. These mostly had a retirement age if 60 and some of 65, with payouts being based on years of service and the final salary. At that point, it was ruled that workers younger than a certain age would be moved to the new Career Average schemes (with a retirement age if state retirement age...so 66/67/68 and payouts being based on salary of each year worked and not all based on final salary) starting in 2015, but older workers would remain in the Final Salary scheme.
This was all implemented in 2015 as planned. However the government were challenged that it was age discrimination and the Supreme Court ruled against them. The consequence is that workers who were in the public sector pensions back in 2012 can CHOOSE whether to have the period 2015-22 in the old final salary or new career average scheme and choose as they reach retirement.
Essentially, for most (but not all) older workers, getting the extra 7 years in the old final salary scheme is better and means they will be able to retire sooner. Why? Because firstly the final salary pensions pay out for most at 60 instead of 66/67/68 like the career average. Additionally, the payouts are usually larger as based in final salary which for most tends to give a higher calculation as workers earn more later in their career (final salary can be last year or best 3 averaged in final 10 years) . All this means those workers can retire sooner with more than if they had the new system for 2015-22.
From 2022 everyone will move to the new Career Average system. 2022 is the date because at that point all workers would have moved to the scheme anyway so there is no longer any age discrimination.
Millions of public sector workers, especially those in their 40s and 50s will find they can afford to retire sooner than if the McCloud judgement hadn’t happened. In reality many workers in 40s and 50s have never really tracked their pensions anyway and so will be nine the wiser about this significant gain to themselves, but nonetheless it is one.
This all only applies to those in the public sector defined benefit schemes and not to those in the more typical defined contribution schemes where you pay into a pot which is invested in the stock market and outcomes uncertain.
Re when you can retire, in the public sector defined benefit schemes, there is a pension age at which you can take the full benefits, but it is possible to take them on an actuarial key reduced basis from 55.
With defined contribution schemes you can take part or all of your pension from 55 (rising to 57 in about 6 years time) but of course, your pot has to last you longer.