So much for Digital Britain if BT's in charge - or are they?

My dad’s 95. He’s still working and has just published a book called Treachery. It’s about the incompetence of MI5 in the cold war. A month before publication his broadband went on the blink. I’ve been trying to resolve the problem; replacing the router (twice) and reporting the problem to BT’s “Not-so-help-desk” in India six times. I’ve had a line engineer out. I’ve had an OpenReach engineer out. Still the (intermittent) problem occurs.

Now while I know it’s BT incompetence at a delivering consistent digital dial tone (Pa lives in the M4 corridor) but every day the problem goes on he’s more and more convinced its the intelligence services putting a spoiler on things. Any of you geeks out there know of any way of telling?