This matter was raised under a different thread. In the Waveney valley in North Suffolk a shooting syndicate run by an Italian who lives there released a large number of Red-crested Pochards, Garganey and Marbled Ducks. There were also commoner species like Wigeon and Pintail.
There has been considerable confusion about the law and the following is a quote received from Natural England.
The law used to stae that you could release wildfowl "native to GB" but this has now been revised to "native to European Territory".
The former was just about acceptable but the latter if carried out to extremes would allow feral flocks of King Eider, Steller's Eider, Marbled Teal etc to be established in any European country. Imagine what this would do to the recording of rarities let alone what effect these could have on native species if successful.
Is this something birders should be concerned about? Is it something the birding community should lobby for to effect a more sensible approach?