I've now got information about a few of the Channel/North Sea crossing companies and how they deal with firearms, which may be interesting. Stenaline (Harwich -- Hook of Holland): firearms yes, ammunition no. must be declared in advance by fax with firearm details and permit details and declared at port. No requirement to hand in your car keys. LD lines (Margate-Ostend; Dover-Boulogne etc): firearms yes, ammunition yes. Must be declared at the port. Car keys must be handed in. Channel Tunnel: firearms yes, ammunition "reasonable quantity" (expect to argue it at check-in). I don't know whether this one has to be declared in advance since I've never done it myself. Anybody done the airlines?