Police reportedly left a three-year-old boy in tears after stopping him playing with a remote-controlled car.
He told The Sun officers in stab vests confronted him and his toddler over the use of their "mechanically propelled vehicles", banned under park rules.
He said: "My son just burst into tears.
"I have nothing against the police but is this really the best use of their time? We weren’t causing a nuisance or annoying anyone.
“I explained that they were just battery-operated remote-controlled cars, not the noisy petrol ones.
“But the officers said, ‘We’ll give you a warning now, but if you carry on we’ll issue a caution’.
“I said to the officers I would put my car away but asked if my son could continue playing with his. But they refused.”
Parks and Events Police, separate from the Metropolitan Police, are employed by Wandsworth Council to carry out patrols in the area.
A council spokesman told The Sun: “Battersea Park is extremely busy with people jogging and cycling and officers may have considered the remote controls were causing a nuisance to park users.”