Specialized ships would probably have encouraged Britain to keep trained assault troops organized rather than assembling them only when a crisis began. An interwar experiment appears to have attached Royal Marines at battalion level to an Indian Army brigade for amphibious exercises. That precedent points toward a combined formation, but the Army might have resisted dividing its expeditionary force to sustain it. The alternative was a Royal Marine formation connected to mobile naval bases, which would have framed amphibious troops as advance elements for establishing and defending fleet support positions.
Notable Point · 56:40-58:14
An interwar brigade hinted at a combined amphibious force
An interwar exercise formation mixing an Indian Army brigade with Royal Marines shows one route Britain might have taken toward a standing assault force.