Government figures suggest some delivery drivers are operating without valid work permits, but it is not clear how many.
A number of staff groups remain in formal dispute with the Government over pay.
Potential figure of 13.7 million migrants was estimated over a longer period than suggested.
Most people are homeowners by the age of 36, but the average first-time buyer is younger.
The proportion of those aged 65 or over paying income tax was 62% in the year ending March 2023.
