Luhe- If true that he pled guilty he will serve time. I am not a lawyer but it has happened in my state that the case was made that Arkansas could not protect the safety of its prisoners to such an extent that it violated their constitutional rights. ( it was seen as cruel and then usual punishment to be incarcerated in Arkansas in the late 60s through the 70s )The federal government provided oversight for 13 years in this state. Perhaps this approach could help Tommy (and others) who have no security in U.K. prisons.
I would leave off indignation at his arrest . That looks like a waste of time. Get the records on the prisons records of insufficient staff and Tommy’s past experiences with incarceration. Concentrate on the very provable charge that the state cannot guarantee his safety.
edit: On my previous post-sorry that first link on U.K. Prisons is a dead number. The second link is good