Back in 1967, Lord Rathbone was one of several British millionaires who were victimized by a ruthless blackmailer named Nathaniel Needle. Needle would stage their "deaths" in order to give them a taste of what might happen should they fail to pay up.
Lord Rathbone survived the traumatic events thanks to John Steed, top professional, and Emma Peel, talented amateur. But it's apparent from watching 'The Avengers' episode "You Have Just Been Murdered" that Rathbone was weakened physically as well as mentally by the ordeal.
I wouldn't be surprised if he succumbed to a heart attack not long after.
If so, it's pozz'ble, just pozz'ble, that "Twiggy" Rathbone, perhaps as a younger brother, came to inherit the title from his childless older brother. It was never stated exactly what the first Lord Rathbone did to become a millionaire. He could have been a newspaper baron of Fleet Street, and Twiggy Rathbone took over that livelihood as well.
And one of the papers in his publishing empire of Rathouse, Ltd. would have been the Crucible, as seen on 'Hot Metal'.
Just a thought.....