Electrical query

CaravanCook101

Hello, I wonder if anyone has come across this problem before and can offer me any help or advice. I tow my Swift caravan with a Vauxhall Inisgnia.  Recently after hooking the caravan up, I get a warning light in my car to say 'check left trailer indicator
lamp'  The indicators start to flash at double speed and then none of the lights work on the caravan.  Has anyone else experienced this and do you know if the problem is likely to be with the car or the caravan.  We have checked all the caravan bulbs and they
all seem to be fine.