More dogs are being exercised on Hampstead Heath than ever before as professional walkers flock to the green acres following the introduction of licences at other parks.

Royal Parks, which manages Regent’s Park and Primrose Hill, introduced paid licences for commercial dog walkers last April.

But many have dodged the fees and switched to the Heath instead, according to the head of the Hampstead Heath Constabulary, Richard Gentry.

He said: “More and more people are coming to Hampstead Heath with their dogs in general and dog control for us is very important.

“We’re going to engage more with commercial dog walkers and other people with groups of dogs.

“We want to make sure the Heath is safe and pleasant for all users.

“There are concerns that people with large groups of dogs are not always able to keep an eye on all of them, or to pick up after each of their dogs.

“There are also fears around safety and that the dogs may act as a pack.”

The increase in dog walking will be the Heath police force’s prime focus over the next 12 months, with a series of engagement projects aimed primarily at commercial walkers.

Mr Gentry believes the rise is largely down to the introduction of licences for commercial dog walkers at the Royal Parks, which cost £300 a year and has resulted in many of them switching to the Heath, free of charge.

He revealed the constabulary dealt with 92 dog-related incidents in 2013, compared with 45 – less than half – five years ago in 2009.

There were three prosecutions against dog owners in 2013, but dozens more received formal warnings.

The Heath welcomes about one million dogs per year, according to the City of London Corporation.