Trafficators

Over the years I have had many car/caravan combinations and have always had either a visual or an audible warning that the trailer indicators are functioning.

I have changed the car and had a tow bar fitted. The electrics are fine but there is no system to say the indicators are functioning. When I queried this I was told that the law has changed and warning devices do not now come with the towbar electric kit.

\is this correct?