Could Lion-class battleships have entered service by 1942?

Would the Lion class have had to wait until 1943 because of problems with its 16-inch guns?

Probably not. The first Lions could plausibly have appeared in 1942, with construction pauses causing more delay than the solvable gun and turret problems.

In the delayed-war scenario presented here, the King George V class could have been complete by late 1941, allowing the first Lions to follow during 1942. Difficulties with the 16-inch gun and efforts to reduce turret weight are compared with earlier weapons whose faults were corrected during production and service. The more damaging factor was the wartime pause and attempted restart of the programme. Technical problems therefore have to be weighed against the institutional and industrial cost of interrupting construction.