The French could stop the boats using their own laws of navigation:
"In French waters, a boat licence is necessary to be able to operate a boat when the power of the motor or motors exceeds 4.5 kilowatts or 6 horsepower. There are three different licences:
- Carte Mer - daytime coastal sailing, 6 to 50 HP;
- Permis Mer Côtier - nighttime sailing, further offshore, over 50 HP;
- Permis Mer Hauturier - high seas, all forms of boating.
I put it to the committee how many of these people hold the correct licences to navigate in French waters. So, as soon as the dinghies are afloat the French authorities do have the right of arrest. Problem solved.