A local authority has admitted that it spied on a family trying to get their daughter into the local nursery school.

The officials from Poole Borough Council in Dorset kept a log of the family’s movements during the two-week stakeout. They tailed the mother for two hours each morning and afternoon as she did the school run with her three children. Later they returned to watch the house.

Investigators logged details such as “Female and three children enter target vehicle and drive off”, and “Curtains open and lights on in premises”.

The investigation came to nothing because the family were doing nothing wrong. They became aware that they had been under surveillance only when it was let slip at a meeting at their daughter’s new school.

The family came to the council’s attention when they applied for their three-year-old daughter to go to the school that their two older children had attended. They intended to move house, and checked with the council to ensure that their daughter would not be denied a place.

They were told that as long as they were living within the catchment area at the end of January their daughter would be able to start in September. The family decided to delay their move until the February half-term.

The mother, 39, a businesswoman who asked not to be identified, said: “We followed the council’s advice and only moved after the date they gave us, but still they stalked us. We even turned down an offer in October because we knew we couldn’t move until after January.

“I can’t imagine a greater invasion of our privacy. Councils should be protecting children, not spying on them. It was very creepy when we found out that people had been watching us.”

The council was acting under the Regulation of Investigatory Powers Act (Ripa), introduced in 2001. The council has admitted to using the same powers six times in the past year.

James Welch, legal director of the human rights pressure group Liberty, said: “It’s one thing for antiterror police to use covert surveillance, but it has come to a pretty pass when it becomes the tool of the school catchment area police.” Tim Martin, head of legal and democratic services at the council, said: “On a small number of occasions, Ripa procedures have been used to investigate potentially fraudulent applications. In such circumstances, we have considered it appropriate to treat the matter as a potential criminal matter.”

Times recommends

• Students abandon the drink for gyms and juice
• Ofsted: third of Baby P-style reviews inadequate
• Top boys' school picks first woman head