Passport checks on all cross-channel and Channel Tunnel travellers leaving the UK are being introduced today under a new Home Office scheme.
The scheme, which is being phased in at ports and border crossings, hopes to give "a much clearer picture of who is staying in the country when they have no right to be here" as well as tracking unwanted criminals and terrorists.
The exit checks have been reinstated as part of the new Immigration Act 2014.
The changes will be phased in gradually with 25% of passengers being fully checked in April. After a month this will be increased to 50% and then to 100% by the middle of June.
A P&O Ferries spokesman at Dover said: "We are hoping that there will be a fairly seamless transition to the new system."
The new system will not affect plane passengers and coaches carrying British or European children aged 16 or younger will be exempt from the checks.