I was just about to ring the Labour Force Survey number to ask about participation rates for 64-year old men.

Assuming that there are just 150,000 64-year old men in employment anyway what percentage are living in such penury that the lack of a state basic pension will force them to continue to work at 65?

100,000 seems optimistic and multiply this by say £20,000 average earnings p.a. (again optimistic given that a significant number of 64-year olds will be working part time and that a recent Harris Poll indicates that only 32% of UK retirees expect to ‘rely’ on the state pension so most will probably still retire at 65 anyway) and you get £2 billion a year.

The extra tax and NICs received from £2 billion earnings can’t be worth more than say £500m or so to the Treasury.

But wouldn’t those 100,000 (or whatever) ‘extra’ jobs have been filled by younger people who would have paid those taxes anyway?

AFAICS that £13bn is a purely theoretical construct based on an NIESR model of what would happen to GDP and the deficit if everyone – bankers as well as binmen – were to extend their fully productive working lives by 1 year.

This does seem to work at a theoretical level but in practice would only produce the effect described if the world economy is healthy enough that any increase in the size of the labour force automatically results in an equivalent increase in GDP.

If we are not in a global economic boom in 2016 then it will be much more of a zero-sum game – any reduction in vacancies from people not retiring at 65 will just result in an increase in unemployment for under-65s.

And if as seems likely employers continue to insist that workers retire at 65 so as to replace them with younger cheaper employees – the net effect is more likely to be that there will be more unemployed older people demanding full JSA or (assuming it still exists at all) IB plus whatever pension guarantee is left.