Why Britain studied 22,000-ton carriers

Why did the Royal Navy examine aircraft-carrier designs of about 22,000 tons?

Because roughly six 22,000-ton carriers could fit within Britain's 135,000-ton treaty allowance, compared with five ships at the normal 27,000-ton maximum.

The seemingly arbitrary displacement comes from a fleet-structure calculation. The Washington system allowed the British Empire 135,000 tons of aircraft carriers and normally capped each ship at 27,000 tons. Five ships at the maximum would consume the allowance, whereas designs around 22,000 tons could provide roughly six hulls. The overall allowance remained tight, so fitting in another carrier did not remove the tradeoffs in each ship's capability.