Originally Posted by
knifeandfork
I'm 3,600 miles away from my copy of Debrett's Correct Form, but I thought that although the style Rt Hon was technically applicable to Lords of any stripe, it was never used. A bit like saying I've got my 100m swimming badge, and my 50m swimming badge.
I understood Rt Hon to be mainly employed when addressing non-ennobled members of the Privy Council, though I stand to be corrected.
Use of the title
Rt Hon is limited to members of Her Majesty's Privy Council.
On the issue of criminal offences, it's a really interesting one.
There doesn't seem to be a general law prohibiting impersonation
per se except in relation to the current monarch (in which case you might find yourself locked in the Tower of London

). There are specific offences in relation to impersonating a police officer and impersonating a traffic warden (s90 Police Act 1996 and s46(3)(a) Police Reform Act 2002). But that's about it.
More relevant is whether obtaining any OpUp or other special treatment may be a criminal offence. The most obvious offence would be fraud by false representation (s2 Fraud Act 2006). It's possible there may also be an offence of obtaining property by deception (s15 Theft Act 1968) (but it's complicated by whether an OpUp is considered 'property' and whether
permanent deprivation can be for the duration of a specific flight), but it appears that the offence of obtaining pecuniary advantage by deception (s16 Theft Act 1968) does not apply (because the scope of is effectively limited to (i) banking / insurance-related issues; and (ii) employment).
/MHL
(p.s. don't treat this as legal advice - go ask a criminal law specialist!)