How Can You Prevent Ants Returning After Treatment?

First: Clean the Trail Properly, Once

As soon as the colony is dealt with, wash the entire run with hot soapy water — the floor, the wall, the skirting, the worktop and the threshold. The pheromone trail persists long after the ants have gone and it is a signpost for next year.

This is the one job to do immediately rather than seasonally, and it takes twenty minutes.

Autumn: The Hard Landscaping

Repoint or re-sand the paving joints where the colony was, particularly around the doorstep and along the wall. Where slabs have started to rock or the jointing keeps washing out, that is worth lifting and re-bedding rather than topping up every year.

Also in autumn: clear the gap where the patio meets the house, and check that soil or paving has not been built up over the damp course.

Winter: The Thresholds and the Gaps

Fit or replace brush strips and threshold seals on patio doors, French doors and any door onto the garden. The sliding track of a patio door is the single most common ant entry point in a house.

Seal around the pipe entries under the sink and at the external wall, fill cracks in render at ground level, and close gaps at window sills. None of it stops a determined colony on its own, but it removes the easy routes.

Spring: Remove the Reasons

Before the season starts. Lift pet bowls between meals rather than leaving them down. Move honey, syrup and jam into sealed boxes rather than onto an open shelf. Deal with the residue under the units and beside the cooker, which is what actually feeds them rather than the crumbs on the worktop.

Outside: move bins away from the door, clear fallen fruit, and cut back planting that touches the wall. Aphids on a shrub against the house are an ant food supply in their own right, and dealing with the aphids reduces the ants.

Summer: Watch and Act Early

A single scout is not a problem. A two-way column in the same place two days running is a colony that has found something, and it is far easier to deal with in the first week than in the fourth.

Do not spray it — that breaks the trail gel bait depends on and leaves the colony intact, so it returns in a slightly different place. Treatment is £190 for a flat and £220 for a house, and a colony treated in July does not come back in August.