PEOPLE living in large buildings in the city have been warned about ant infestations that can "spiral out of control" and take over your home.

Experts have raised the alarm on pharoah ants, which can create huge colonies that will split if threatened, proving a nightmare to get rid of.

The tropical pest will only be found in the structures of large centrally-heated buildings such as high-rise flats, student halls and hospitals.

Specialist products can effectively control the insects, which love heat and can frequently found in the boiler rooms or near to ovens.

Natalie Bungay, technical manager the British Pest Control Association said nests can contain as many as 100,000 ants.

She said: “Pharoah ant nests can vary in size, but they can grow to massive proportions, with research finding nests containing 50,000 workers and 100,000 ants in the young stages.

“Only five to 10 per cent of workers forage for food, so a trail of Pharoah ants down the face of a wall or machine is just a small part of the picture.

“The workers may respond to danger by ‘budding’ - sometimes referred to as ‘satelliting’ – and will move pupae and young larvae away from the original colony, which can lead to the ants spreading throughout a building or complex, and the infestation spiralling out of control.”

Professional pest controllers should always be called in to tackle an infestation of Pharoah ants as specialist products and careful surveying are required for successful treatment, the organisation claimed.

Natalie added: “A hormone bait can be used to sterilise queens and prevent larvae from developing, but this system can mean controlling the infestation could take around four months.

“Newer, in-depth surveying and gel bait products mean control can be achieved within two or three weeks, but a carefully planned and implemented strategy, delivered by a professional pest controller, is the key to success.”