Reduced performance

I had driven about 500km yesterday (we are on vacation in Spain) when we made a stop. When turning onto the motorway the car went into reduced performance mode ( yellow triangle). I drove to the next gasstation filled her up (it was half full) and started again. Warning was off but back on the motorway it came back on at when reaching 80km/h.
I then managed to drive it for an other 160km to my hotel, at
max speed of about 120km/h and that is where I am now.
Just tried it again with the car standing still for almost 24hours but the problem is exactly the same.
Below 80 the car drives with full power but once you go above 80km/h it goes into reduced power mode.
Any ideas what might cause this?
Will take it to the local RR dealer tomorrow.

Not sure what the problem is, but you can cheat the reduced performance limit by using the cruise control to increase your speed. Kissy tap up the speed using the + button on the steering wheel

Look under the bonnet to see if there's anything obvious. This happened to me on my old Range Rover and it turned out to be an airhose that was disconnected.

Worth a quick look under the bonnet anyway.

I went to the local RR dealership on Monday and the diagnosed the problem as a damaged turbo tube. They fixed it within 1 hour and I have since driven it from Girona to Barcelona and everything seems to be fine. Total cost 196 Euros.

I did use cruise control while on reduced performance and it went as far as 120km/h but going up hills/mountains it doesn't hold the speed. I dropped back as fast as 80km/h

Thanks for the advise guys.