Poole Borough Council monitored the Paton family on 21 occasions in 2008 to establish which school catchment area they were living in.
Poole Borough Council acted improperly and breached a family's right to privacy after spying on them to ascertain whether or not they lived in a school catchment area, a tribunal has ruled.
Mother of three Jenny Paton and her partner Tim Joyce were placed under covert surveillance for a period during 2008, with local authority staff monitoring their movements and describing their car as a "target vehicle".
The council used legislation under the Regulation of Investigatory Powers Act (Ripa) to watch the family's movements.
Speaking to BBC News after the ruling, Ms Paton said: "It is absolutely brilliant. We are hopeful our case will highlight local authorities' misuse of Ripa [powers]."
She added that the council did not consider the impact of putting children under surveillance.
Alex Deane, director of campaign group Big Brother Watch, said last year that abuse of Ripa legislation had become a widespread problem in the UK.