Wall Lizards are not a native species in the UK. However, that hasn't stopped a number of individuals illegally releasing them into the wild from captive stock in the last few decades in Dorset. I saw my first Wall Lizards in the main quarry in Winspit in 2005 & 2007. I have seen them on more recent visits, albeit I don't visit Winspit as much as I should do & I haven't looked too hard for Wall Lizards when I have visited. So, I don't know if they still occur there or not.
In Oct 22, I heard that it was possible to see Wall Lizards on the castle wall at Durlston. In a quick look on a sunny Oct day, I managed to see six without any effort. Having a quick look online, it looks like there had been a release in the 1990s & they hadn't fared too well & potentially they had disappeared after a few years. So, perhaps there has been a more recent illegal release.
There are a number of problems with these illegal releases. Firstly, they are breaking the law covering the release of alien species in the UK. Secondly, being an illegal release, the individuals involved will not bothered to consider or care about the impact on the other native species that occur at a release site. This isn't just an impact on Common Lizards at the release sites, but also any other scarce invertebrates that might be present at the release sites. These cowboys who release Wall Lizards will do it with no monitoring of what species occur at the release site, consideration of the impacts of the release, let alone scrutiny & longer term monitoring.
On the bird front, the teams involved with the Poole Harbour Osprey & Isle of Wight White-tailed Sea-eagle releases have had to jump through multiple hoops over many months and presented a lot of evidence to satisfy Natural England that the proposed releases will be legal and will not have adverse impacts on the environment. Additionally, they will have had to put in place carefully monitored with lessons learned for releases in future years. The same will undoubtedly be the same with the Butterfly Conservation release of Chequered Skippers a few years ago at an English site.
There are clearly a lot of potential problems caused by illegal releases & it would be great to see the individuals involved with the illegal releases being investigated & ultimately some prosecutions would be nice to see.