There are three species of snakes in the UK; adders, smooth snakes and grass snakes. They are all protected under UK law. There is a wealth of information online from sources such .gov.uk (https://www.gov.uk/guidance/reptiles-protection-surveys-and-licences) and The Wildlife Trust webpages (http://www.froglife.org/info-advice/lizards-identification/).
Some activities such as building work, may affect snakes. If this is the case, due to their protected status, you might need to provide compensation or mitigation for them. Because of this, if you are planning to develop a site you could be required to survey the area to find out if any snakes are around. For more information check out our video on Snakes and our previous video on Lizards.