A further nine children were working illegally on stalls.
The exercise was a joint initiative between the two services, working in partnership with local schools and United Racecourses, and followed reports of children seen at the market on school days, either alone or with their parents. A large proportion of the children stopped were from outside the Spelthorne area.
Principal education welfare manager, Sue Howe, said: 'The initiative was welcomed by the event organisers at Kempton Market. Due to its success, it is likely to be repeated at other venues across the county.
In all cases where children were stopped at the market their schools will be informed, regardless of whether an adult was with them, and unaccompanied children were told that their parents would also be notified.
Where children were working illegally, appropriate warnings were given to the employers.