From what is written in the CBP-7540:
"10.21 million people of working age 16-64 who reported they were disabled." I will actually question here, why do they count 16-18 years old? They should do their A-levels, not working! Same with the 18-24 years old - they should study and not work full time! Some degrees, like doctors require to study longer than up to 24 years old.
"5.53 million working age people in employment who reported they were disabled" - what the government wants from them? These people already work, they pay taxes like everyone else!
At the end we are left with 4.68 million people who are disabled and unemployed.
Based on CBP-9366: researchbriefings.files.parliament.uk/documents/CBP-9366/CBP-9366.pdf
32.98 million of people age +16 should be in employment.
They counted separately, 32.98 million people working age + 10.21 million people disabled = 43.19 millions people in total of working age. If we'll count 4.68 million disabled people not working from 43.19 millions that will be 10.83%. Far away from 25-30%.
They write 24% of the working population is 10.21 million disabled people in CBP-7540. In CBP- 9366 they write that 100% of working age people are 32.98 million. That means they counted separately disabled people and separately working population.
43.19 million people of working age +16 = 100%
32.98 million people of working age +16 = 76%
10.21 million disabled people of working age + 16= 24%
5.53 million disabled people in employment = 12.80% from 43.19 million of people
4.68 million disabled people not working = 10.83% from 43.19 million of people
Also, don't forget that 4.68 million disabled people who are currently unemployed are kids between 16-20 years, people who worked but for health reasons can't work at the moment for up to a year or two. They will go back to work. Is far away from 25-30%.
Based on gov.uk only 2.6 million disabled people receive PIP = 6% of total 43.19 million people of working age +16. I'm not sure what's all the talk about if at the end only 6% of the population are disabled enough to qualify for PIP and rest of the disabled people 7.61 million don't qualify for it and most of them work?
www.gov.uk/government/news/disability-benefits-system-to-be-overhauled-as-consultation-launched-on-personal-independence-payment--2