Ant control in London

Black garden ants, 88.5% of the winged ants in the Royal Society of Biology's national survey, live in colonies of 4,000 to 7,000 workers underground, commonly under stones or paving. The workers you see are foragers on a scent trail, and that decides the method.

• Spray: kills the foragers it touches, a few hundred from a colony of thousands; the queen keeps laying and the trail re-forms.
• Gel bait: slow-acting, professional-use, dabbed on the trail. Foragers share it through the colony, brood and queen included, so the nest dies rather than the trail.
• Dust or residual: at an outdoor nest, in a wall void or at entry points. Used with bait, not instead of it.

Species changes the bait. Ghost ants (1.3 to 2 mm, dark head, pale body) and Roger's ants (2.5 to 3.2 mm, yellow-brown) live in heated buildings and take a different bait; pharaoh ants must never be sprayed, because spraying splits the colony.

A single garden ant trail into one room is the cheapest job. The cost rises with the number of nests, the rooms or flats with trails, a nest in a wall void or under a floor, and a heated-building species that needs more than one visit; pharaoh ants are quoted separately.

Some London boroughs no longer run a pest service, and those that do charge for a single garden-ant visit: Wandsworth Council £71 for one treatment from 1 April 2026, Hammersmith and Fulham £73, Lewisham Council £150 from 1 April 2026, Brent £115 and Hounslow £165 at October 2026.

Our inspection survey is free, the quote is fixed and in writing before any work, and there is no call-out fee. Every treatment carries a written six-month guarantee, subject to the site survey.

Before we arrive:

• Leave the trail alone: no spraying, wiping or bleaching; it shows us the entry point and is where the bait goes
• Clear under the sink and fridge, and put sweet food, pet bowls and the bin out of reach so the bait is the best meal available
• Note every room with ants; a photo is enough

After the visit:

• Gel bait needs no vacate time; where a dust or residual is applied outdoors or in a void, keep off it until dry, as the label states
• More ants on the bait for a day is the treatment working; trails thin over the following days, a multi-nest colony over a few weeks
• Do not clean the bait points away, and keep children and pets off them
• Keep sugar and pet food sealed and wipe spills; a new colony will follow any trail an old one left
• If a trail returns or a second appears, call us; the guarantee covers the return

Ants are a nuisance rather than a hazard in law: the Prevention of Damage by Pests Act 1949, which obliges occupiers to report substantial numbers to the council, covers rats and mice only.

In a rented home, Shelter's guidance (updated 1 May 2026) says the landlord must deal with pests that get in through a repair they should fix, must keep the home fit to live in (the duty behind the Homes (Fitness for Human Habitation) Act 2018) and must sort out an infestation present at the start; a tenant who leaves food and rubbish out is responsible for the ants that follow.

A persistent infestation in a block is a domestic hygiene hazard under the Housing Act 2004 HHSRS, and the council must act on a Category 1 hazard. Awaab's Law adds electrical, cold and fall hazards for social landlords on 30 November 2026 and is due to reach pests in 2027; a consultation on private tenancies closes 18 December 2026.

Garden ants need soil, warmth and a gap, so the work follows the housing. The terraces of Clapham and Tooting, with patios laid against the back wall, give a nest a warm wall and a way in, as do the Victorian streets of Fulham and Chiswick. In Wimbledon, Richmond and the TW postcodes the nest is more often under a lawn or decking.

Flats are different. A yellow rather than black trail in a mansion block in Kensington or Westminster is usually pharaoh ants, and a pale, hard-to-see ant in a heated new-build may be a ghost ant. Hart and colleagues found urban nests and those beside heat-retaining structures fly earlier, so London's flying ant season leads the national curve.