Why the Tigers sailed without Bofors

Why did the Royal Navy give up 40 mm guns on the Tiger class?

It did not abandon Bofors; the ships were fitted for them but not with them because omitting the guns reduced completion cost.

The Navy had not rejected Bofors; it continued fitting them elsewhere and reserved mounting spaces on the Tigers. Those empty positions remained visible around the superstructure and could have accepted guns quickly if required. The automatic three- and six-inch batteries already looked formidable enough on paper to support a gun-only argument. Leaving the 40 mm weapons out therefore saved money under the cheapest completion option, while fitting them would have moved the ship toward the medium-cost proposal.