An Office for Nuclear Regulation (ONR) spokesperson said: “We were informed about a serious construction incident at the Atomic Weapons Establishment Aldermaston site on 6 July, which has resulted in a construction worker fatality.
“Our thoughts are with the deceased’s family, friends and colleagues at this tragic time.
“We have staff on site and are working alongside other relevant authorities including Thames Valley Police who have initial primacy and are currently leading the investigations on site.
“As this is a live investigation, we will not be commenting further so as not to prejudice those inquiries.
“The incident did not involve any nuclear materials and there are no radiological consequences to the public.”