Smart meters are covered by strict product safety laws set by the UK government. Public Health authorities do not believe smart meters pose risks to your health. The exposure to radio waves from your smart meter are well within guideline levels and are many times lower than those emitted by your Wi-Fi and mobile phone.
Security was at the heart of the creation of the UK's smart meter programmers and the system has been designed specifically to prevent hacking. Smart meters don't use the internet and all communications are run through a closed system dedicated to smart meters. They don't retain any personal information.