If you want absolute power you are looking at 1964 before the Valiants were withdrawn - 4 x Victor 1a, 2 x Victor 2, 3 x Vulcan 2 BS, 3 x Vulcan 1a, 3 x Vulcan 2, Valiant
PR, Tanker and TBF. Runs out at about 18 V-force ac on QRA armed with megaton weapons. Countless Canberra sqns in Germany also on QRA.
How do you really stipulate one peak in 90 years? There are many peaks and troughs.
Obviously immediately at its formation it was a most powerful force which, with peace, immediately started to decline.
A peak can then be considered in the 20s and 30s with air policing in Africa and Mesoptamia.
In parallel with this peak was the decline in adherence to biplane technology.
At the same time the air base design, in particular the hangar designs and base locations was a peak.
RAF strength in 1938-42 was also a trough until the massive buildup of the TAF, Bomber, Coastal and Fighter Commands.
How do you measure the WW2 highs of 1944-45 with the 1960 highs of nuclear deterence or the precision capability of the few in 2000-2009?