Pharaoh ant control in London

A pharaoh ant colony has many queens, each able to lay up to 350 eggs a week according to Redbridge Council. The BPCA puts the risk plainly: when threatened, workers may bud, moving pupae and larvae away from the original colony, which can spread the infestation through a building.

• Spray, fogger or dust on a trail: kills the foragers in reach and triggers budding, so one nest becomes several. We do not use them on pharaoh ants.
• Hormone (insect growth regulator) bait: sterilises the queens and stops larvae developing, but the BPCA's technical manager says control this way can take around four months.
• Surveyed gel baiting: a professional-use gel on every active point a proper survey finds; the same BPCA source says control can be achieved within two or three weeks.

Garden, ghost and Roger's ants are covered on our ant control page.

The number of flats or rooms with active trails is the main driver, because every active point has to be baited at the same time or the colony moves. After that: the follow-up visits the programme needs (two or three is the council norm) and whether a managing agent or care home needs reports and a block-wide plan.

Lewisham Council charges £186 for up to three visits from 1 April 2026 and Wandsworth Council £214 for tropical ants, three treatments, from 1 April 2026; Hammersmith and Fulham lists £167 for two visits, Hounslow £210 and Brent £287 at October 2026.

The inspection survey is free, the quote is fixed and written for the whole programme, follow-ups included, and there is no call-out fee. Every treatment carries a written six-month guarantee, subject to the site survey.

Before we arrive:

• Stop spraying: shop sprays, foggers and powders split the colony, and the visible trail is where the bait goes
• Note every room and flat where you have seen them; in a block, tell the managing agent so neighbours can be surveyed too

After the visit:

• Gel bait needs no vacate time and nothing is sprayed
• Do not clean the bait points away: Redbridge Council's programme puts this rule first, and it is the commonest reason a treatment stalls
• Expect a noticeable reduction within about 28 days, the council benchmark; with gel on a well-surveyed site the BPCA figure is two to three weeks
• Larger ants appearing late in the programme is a good sign: the workers have gone and the queens are out foraging
• The follow-up is four to six weeks on; if ants persist four weeks after the final visit, we come back under the guarantee

In a block the freeholder or managing agent usually ends up responsible in practice, because the colony moves between flats. Shelter's guidance says a landlord must deal with pests let in by a repair they should fix or present at the start of the tenancy, and must keep the home fit to live in, the duty behind the Homes (Fitness for Human Habitation) Act 2018; a tenant is responsible only if their own conduct brought them in.

Pharaoh ants in a block are a domestic hygiene hazard under the Housing Act 2004 HHSRS, and the council must act on a Category 1 hazard. Awaab's Law is due to reach pests for social landlords in 2027, with a consultation on private tenancies open until 18 December 2026.

In healthcare and care homes, CQC Regulation 15 requires premises to be clean, suitable and properly maintained, and Redbridge warns that pharaoh ants may invade surgical dressings and spread infection between patients. Food businesses must have adequate pest procedures under Regulation 852/2004.

Pharaoh ants are a heated-building ant: the BPCA finds them only in the structures of large centrally heated buildings such as high-rise flats, hospitals and bakeries, often around boiler rooms and ovens. In our area that means the post-war estates and mansion blocks of Westminster and Pimlico, the heated towers of Camden and the new-build developments along the river in Battersea and Wandsworth, where shared risers keep a colony at breeding temperature all year.

Hospitals, care homes and bakeries in Hammersmith, Hounslow and the TW postcodes get the same programme with the reporting their regulator expects. A single house in Richmond or Wimbledon is rarer; the survey still covers the whole building.