Hmm, politics is not my strong point. We have a parliament (all voted in), and the party that holds the majority forms the government. The Government splits into different Ministries (Defence, Foreign Affairs, Home Office, Treasury.) then they have little sub division too (Work and Pensions would come under Treasury for instance.) Each department has a Minister in charge of it and then the Prime Minister is in charge of them. Technically, the Queeen is the Head of State, she doesn't have any real power but she has a lot of influence.Lalala.. so, I suck at understanding British politics - do they have one Minstry with different departments (defence, home politics, education), or is it one Ministry per... thing, like "Ministry of Defence", and so on, which then again have different departments? I think (from what I gather from my google research, but I suck at understanding things late at night) the latter one, because then the Ministry of Magic fits into the rest of the system very neatly, but I want to make sure.
Yes you can use 'is pissed' - that's rude (ish) so if you want something else you could say
'he's bladdered' (lovely connotation ha ha). Bladdered is probably more of an 80's/90's expression so it really depends which era you're writing.
We used to use 'bevvied' at one time (bevvy being short for beverage), or 'out of my tree'
'trollied', (Oh, they're all coming back to me now).
Not sure about 70's era 'pickled', 'pissed as a newt' or just 'really drunk'.