Don t know if it's serious, but getting very interesting ..
Case: conspiracy to murder.
Questioned =
Probably Yes
The Police will ask him to come to the station and be questioned alongside his Solicitor, if he doesn't have one (highly unlikely) a duty Solicitor will be provided to him then he will be released.
Police then gathers evidence. CPS (Crown Prosecution Service) then weighs prosecution since this isn't in British Public Interest it is highly unlikely that CPS will waste taxpayer money on prosecution.
At best, British Government may ask him to leave UK voluntarily (depending on his legal status). If he has permanent leave to stay then even that can't happen.
There are 3 scenarios in which my assessment above will not be valid:
- Smoking Gun evidence of his involvement is found which CANNOT be refuted/ignored
- Pakistan Government brings unprecedented diplomatic pressure on British Government to Prosecute (based on 1)
- British Media picks up this story (based on 1) and this becomes politically embarrassing for British Government
P.S: In Pakistan when he is questioned by the Police the Media will label that as 'Nawaz Sharif arrested...'