Taken - the basic NHS pension contirbution is 5-8.5% of gross pay but if you are paying 12% then possible you are paying into an AVC.
The pension you get for this depends on how many years of service you have and is calculated as no of years of service * 1/80th or 1/60th of final/average pay depending on which bit of the scheme you are in.
Have had a quick look at the old police scheme (which I presume your BIL is in) and its based on 60ths until you have done 20 years and then it goes to 30ths. So yes the proportion is much higher than the NHS scheme.
So now I'll have a guess at why its like this (pls all this is just me trying to put some kind of logical explanation to it - so may not be correct but I'm just trying to look at the figures alone rather than talking about who deserves what)
I'm guessing it was designed in this way at a time when police life expectancy post retirement was a lower. I haven't been able to find the exact figures anywhere but I would imagine that the life expectancy of policepeople was lower than the whole range of NHS staff (which includes all kinds of jobs such as admin staff/ maintenance people etc which are probably a lot less demanding on your health than being a policeman) who are covered by the NHS scheme. .
This is I suppose why the whole thing is being looked at now in line with almost every other final salary scheme. It is no surprise that the majority of pricate sector employers no longer run such schemes as increased life expectancy means they were all running up defecits.
However I think that in the end public sector schemes are underwritten by the tax payer and so its partly down to all of us citizens as to whether its possible/ desirable to underwrite such schemes or whether we would rather our taxes be used for something else.
BTW - thanks to all you lovely police and nurses out there - I truly appreciate you all.