A trail leads two ways
The trail thickens the longer it's left, since every worker making the same round trip reinforces the same scent path, whether that's near Highgate, where georgian and Victorian housing on high ground, or elsewhere in the borough. Wiping the trail away only clears what's visible, following it instead shows where the colony really is, just as near Belsize Park, where victorian villas and mansion blocks between Camden Town and Hampstead.
Locating the entry point

Pick a warm, settled part of the day when activity peaks, and watch the line as it runs away from wherever the food was found. In Camden's terraced streets, a basement door threshold, a gap around pipework, or the edge of an airbrick are the most common entry points.
Terraced streets in Kentish Town and Gospel Oak

Ants come into kitchens and basement flats through gaps at doors and airbricks especially often in the terraced streets of Kentish Town and Gospel Oak, where small front areas and narrow side returns give colonies a warm, sheltered spot right against the house wall.
What to leave alone for now
- Spraying the visible trail, which kills foragers and leaves the colony untouched
- Pouring boiling water into paving, which can crack mortar and rarely reaches the queen
- Filling the entry gap before the nest itself has been treated
- Scattering loose powder along the trail, which can split one colony into several
Sealing the gap afterwards
With the colony dealt with, go back and close only the gap the ants were actually using, a threshold, pipe hole, or crack in old mortar, true near Kentish Town too, where victorian terraces split into flats. Weep holes and air bricks should stay clear, sealing them shut only traps moisture inside the wall, just as near Camden Town, where dense Victorian terraces and converted flats around the market and high street.
Booking ant control in Camden
Ant control in Camden runs £190 for a flat and £220 for a house, and because around Primrose Hill, where elegant Georgian and Victorian terraces close to the park, it helps to say roughly whereabouts in the garden the nest might be when you book ant control, with the rest on the Camden ant control page.

