ATA carnet procedures: third country carnets - offices of entry and exit
Istanbul Convention Articles 1(e) and 18
Under the terms of the Istanbul Convention, the EU is regarded as one customs territory. Therefore, goods entering the EU under cover of an ATA carnet are only presented at the office of entry (the first customs office met on entry) and at the office of exit (the last customs office before leaving the EU). Movements between Member States are made without declarations at internal frontiers.
This means that goods presented at entry to the EU in the UK may well exit from another Member State; the reverse is also likely.