Contract manager Stephen Webb and grounds maintenance officer Dominik Ciemierz, both from contractor John O'Conner, join dozens of other grounds maintenance and green space staff who hold similar powers across the country.
According to the latest Home Office figures, there were 2,219 accredited people at the end of 2010, of which more than 50 were grounds staff, rangers or park wardens.
Webb and Ciemierz's powers are restricted to Hertsmere, where they can request the name and address of anyone they suspect of causing anti-social behaviour. They can also confiscate alcohol from anyone they think is under the age of 18 who cannot prove otherwise.
The Community Safety Accreditation Scheme is run by police forces. Volunteers are vetted and attend a two-day training course.