In the context of total UK payroll expense, your figure of £32m is an insignificant number.
It appears to have been calculated by assuming that 16% of the workforce are not just under-performers, but are complete non-performers, so their entire salary is wasted. But it is based on a sample size of only 9,000 employees (£32m = £22k x 9,000 x 16%). In fact, using the same assumptions that 16% of the workforce are complete non-performers, and that the average wage is £22k pa, the cost to UK employers as a whole – assuming an employed workforce of about 20 million – is around £70bn.
Forester UK Group