We studied the spread of a small leaf-mining moth [Phyllonorycter leucographella (Zeller), Gracillariidae] after its accidental introduction into the British Isles. At large geographical scales, previous work had shown the spread to be well described by a travelling wave of constant velocity. Here, we report the pattern of spread at scales of 1 km2. By locating all bushes of the insect's foodplant (Pyracanrha spp.) within 1-km2 quad- rats, the precise pattern of colonisation at finer spatial scales could be established. Where the 1-km2 site was colonised by moths from the main advancing front, no spatial pattern in the order that bushes were infested was found. If the source of colonisation was a single or small group of infested plants within the site, there was some evidence that nearby plants were colonised first. We found no evidence of population turnover after colonisat- ion. We interpret the results in terms of a two-stage mod- el of invasion that produces different patterns at small and large geographical scales.