A London council is charging personal fitness trainers £350 a year to use its public parks.
The fee was introduced by Hammersmith and Fulham council on 1 April, costing personal trainers £29 per month to use its 48 parks and open spaces for business purposes.
The annual licence fee for one-to-one training is £350, which increases to £1,250 for training large groups of people.
Police are on patrol to check fitness instructors have licences.
The fee was introduced to "restore balance" against commercial businesses "taking over" some parks, according to a council spokeswoman.