I'm sorry to hear that. It sounds to me as if the camera is getting power, but the circuitry that controls and 'drives' it is not initializing... or at least, the video circuitry is not.
Is there any evidence that its other functions work, aside from the screen, that you may notice?
You might try removing the batteries, and leaving the camera on a (dry, non-humid, non-dusty) shelf for overnight. Then put the batteries back in and try the camera again.
In any case, I think that it will, most likely, need repair-servicing. Nikon UK repair may be found here:
I hope that this helps, but let me know if you need any other advice on this problem. Thank you.