alt Hacker NewsIn granite bedrock areas such as Cornwall, yes, radon is a significant concern that requires measurement and usually remediation (extraction fans).
The chalk bedrock in Reading isn't generally susceptible to radon.
UK radon mapping data: https://www.ukradon.org/information/ukmaps
The map shows Reading does have some radon. Probably not at such a level most people do anything about it, but for a basement you'd definitely be better safe than sorry.