Scary as it is, you can practice as a "counsellor" in the UK without a license or a degree.

But you can't register with the British Psychological Society and you probably wouldn't actually get a job as a counsellor - you could just practice on your own (no, I am NOT suggesting this is a good idea AT ALL - just telling the story....) To register with the BPS is a very long and tedious process that will involve (probably) doing a conversion course to convert your US degree to an English honours degree, doing a Master's to obtain the Graduate Basis for Registration, and then doing some sort of further work after that to get full registered status (there are many routes for this last bit - all outlined on the BPS website.)
It took me MONTHS to get a job even remotely related to psychology/counselling and I've got an Advanced Diploma (aforementioned conversion course) and am a bit more than half finished with my MSc.
It's a long haul, but it can be done.... Good luck!