The agreements must have been concluded with a reservation for subsequent legal actions as well as approval by the government and, where relevant, the parliament. On 4 January 2016, ID checks were introduced for all train, bus and boat passengers traveling from Denmark to Sweden. On the same day, the Danish Prime Minister announced that Denmark would introduce temporary border checks for those travelling from Germany to Denmark. Until then, transport companies were responsible for checking the identity of passengers while they were still on Danish soil. Train passengers were therefore required to change trains at Copenhagen Airport and go through the identity checkpoint. Likewise, HH Ferries had introduced ID checks of all passengers travelling to Helsingborg at the ferry port in Helsingor.