The RSPCA (in general) represent nothing more than a bunch of bunny hugging short sighted morons usually on a power trip. Their grasp of reality is highly questionable, however they unfortunately do some good work which helps fund some of the more stupid things they do, such as getting involved with areas they know very little about.... such as tail docking.
Which RSPCA are we talking about here?
That's not intended to be a flippant question, because in my experience there are 2 very separate groups...
There are the inspectors and local volunteers, often misguided but well meaning people who do their best for animals.
And there's the headquarters staff, overpaid and overqualified people whose job it is to formulate policy, 'educate' the public and politicians and raise money, at the same time doing their level best to avoid 'wasting' money on things like animal welfare.
Harsh words? How about their 'Freedom Foods' scheme? It means absolutely nothing in terms of animal welfare because all that participating farmers actually have to do is to 'aspire' to improve the lives of the animals involved - and pay an annual fee for their right to use the logo.
Many years ago I was a Branch Chairman. It took me a while to realise that the only valued function of branches is to raise money for headquarters, and to act as unpaid inspectors, and especially in areas like ours where they didn't even have an inspector. In fact I came to realise (eventually) that my main qualification as far as they were concerned was that I held a Firearms Certificate, so could deal with the unwanted animals for them.
Personally I don't feel that drowning is acceptable (although of course thousands if not millions of rabbits are accidentally drowned in their burrows in heavy rain and flooding) but not everyone has access to a shotgun and not everyone can bring themselves to hit an animal with a spade, but surely advice would have been better than prosecution?
And as for taking it to a vet for a lethal injection, imprisoning and transporting a wild animal would be torture, not kindness.
A year or so ago, a local farmer was prosecuted by the RSPCA for shooting dogs that he caught in the act of attacking his sheep - fortunately the magistrates had more sense than the RSPCA and the case was dismissed