The problem is the combination of game bird release without predator control. You could ignore the predator control if we weren’t putting out millions of game birds for the predators to feed on - there’s not enough song birds for them to survive on. But if we keep pumping out game birds over autumn/winter then predator control is a must as without it the song birds will get clobbered by the artificially high predator numbers.
Dissapointing to hear that argument raised by a member on here. It's increasingly pedalled by antis pushing for a ban on driven game shooting.
Do released game birds provide an additional food source for generalist predators in the UK. Of course they do. Is this the sole source of the increase in these predators and by doing away with driven shooting you'll restore the "balance". No chance. I would say most estates involved in gamebird releasing will be at the very least performing fox control. Many will be controlling corvid populations also.
As others have said, human activity, in urban, suburban and rural areas provides numerous, ample sources of food to maintain predator populations at levels far higher than the supposed "natural" levels. This, alongside human activity itself, can have a negative impact on the breeding success of other species in those areas.
You could end game bird release tomorrow and there are sufficient alternative food sources for the predators to switch to with negligible impact on their populations.
My view is that we have an obligation to address this imbalance wherever possible, which includes lethal predator control, not just in rural areas. The best you can hope for is to reduce the predator populations at key times of the year to a level where the pressure on the prey populations allows some breeding success. With the best will in the world, in the modern world we live in, that's probably as good as it gets.