What must you check on a car with a caravan trailer before setting out on a journey?

Before you start driving with a caravan trailer, it is required to check that the trailer’s lights—like brake lights, indicators, and tail lights—are working properly, as these are essential for road safety and to signal your intentions to other drivers. You must also make sure that your view through the rear-view mirrors is sufficient, because a trailer can block your normal rear view and you may need special extended mirrors to see traffic behind you.

As for whether people in the caravan have to wear seat belts, passengers are not allowed to ride in the caravan trailer itself while the vehicle is moving, so checking for seat belts there is not relevant. Always make sure these two checks—lights and mirrors—are done each time before you drive with a trailer.