This MI5 guy has been spamming multiple lists/groups - aircraft, ham
radio, electronics, photography, and likely many others that I don't
subscribe to...
Complaints to the list administraotrs get no response...

Anyone know anyone who can get some action to block this guy?

denny

Well, depending on the newsreader you are using, you can create a Message
Rule. In OE, you can also select any one of the messages and use Block
Sender under the Message drop down. Block Sender will apply to future
messages as well as those already in the newsgroup folder, while the Message
Rule will only apply to those messages received in the future.

Personally, I find him/her far less irritating than a Troll. YMMV

Peter