The training requirements for United Kingdom National Private Pilot Licence (NPPL) are listed in the Air Navigation Order and administered by the Light Aircraft Association (LAA).

The syllabus for Simple Single-Engine Aeroplane (SSEA) is here and a summary of minimum training hours are:
32 Hours of flight instruction of which
22 hours of dual flight instruction (to include: 1 hour instrument appreciation) and
10 hours of supervised solo flight time.

The LAA maintains a very useful FAQ page here.