Hampstead Heath bosses have ramped up efforts to tackle a tree disease that disfigures one of the capital’s most iconic species – and are braced for the spread of more serious conditions.

Staff are mounting frequent inspections after some of the Heath’s stock of London planes were hit by massaria, which migrated to the UK from Europe.

Although it does not kill, the fungal disease attacks branches and causes rapid decay that can cause them to break off, deforming the tree and posing a potential risk to passers-by.

Jonathan Meares, City of London Corporation’s tree manager for Hampstead Heath, said: “We knew it would probably make it to the Heath and we found it last year on a number of trees near South End Green. We’re not sure how it got there.

“The more we have looked, the more we have realised it is in other areas as well. We have about 300 London planes and most of these are in very high use areas.

“It can kill branches quite quickly. Once we find it, it’s important to remove the branch then and there, because there’s a potential it will fall off the tree.

“It does require fairly rigorous management from our point of view – it causes us quite a lot of work.”

The Heath’s tree team are carrying out weekly inspections and officers are on alert for more alarming infections.

Mr Meares believes it is only a matter of time before the deadly ash dieback disease and poisonous oak processionary moth strike in Hampstead – and preparations are already under way.

Once a tree is infected with ash dieback, which is caused by a fungus, it cannot be cured.

“Ash dieback is in the background,” Mr Meares said. “There’s a fair amount of ash on the Heath and it will get in. It’s going to have a pretty major impact on our hedgerows. There’s not an enormous amount we can do when it does arrive.”

He said the tree team would look to diversify stock used for hedgerows, which often have young ash trees that are at greatest risk, with alternatives like hawthorn that are not prone to the disease.

Oak processionary moth is a type of caterpillar that colonises oak trees, creating nests with little hairs that can be harmful to humans, causing rashes and respiratory problems.

Mr Meares said trees will be sprayed in an attempt to kill off the blight when it strikes.

He added: “Again, it’s more a question of when it arrives, rather than if. We have about 1,400 oak trees on the Heath. We are putting some plans together as to exactly how we will deal with it.”