Hi Litebulbs.
It is not necessarily the minimum;
from the CAA website -
Flight Time Limitations (FTLs)
The ANO requires AOC holders in most circumstances to operate only in accordance with the provisions of an FTL scheme approved by the CAA.
Schemes compliant with
CAP 37122 - "The Avoidance of Fatigue in Aircrews" will be approved although alternative schemes may also be approved if the CAA is satisfied that an equivalent level of safety will be achieved.
Link at
Preparing an Application | Flight Operations | Safety Regulation