Osculating eccentricities (left plots) and inclinations (right plots) of the trans-Neptunian region after 4.5 Gyr of integration. Neptune undergoes disc migration from 35 au (top plots) and 39 au (bottom plots) and reaches its current semimajor axis at about 30 au. Rows containing three plots highlight the separate coloured components. Blue stars and dots indicate true resonant objects. Compared to the ‘fixed planets’ case, the disc in between 34 and 39 au has been depleted by Neptune’s inward migration. If Neptune starts very close to the CKB region, some of the orange and grey planetesimals end up forming a low-i and moderate-e clump that overlaps in part with the CCs.