I'd like to know how widespread these statements are in the UK. In the movie 'In Bruges' Ralph Fiennes says to, a suddenly, soft-sounding Brendan Gleeson (employed as a hit-man by Fiennes):
You're coming on all-Gandhi,
a sarcastic remark ridiculing Gleeson's non-violent stance toward Colin Farrel (another hit-man).
I suppose a person who gushes about saving the people of the world would draw the comment:
You're coming over all-Mother Theresa.
Expressions of sweetness and light might draw the comment:
You're coming on all-Little Mary Sunshine.
Are these phrases a part of British slang or just one-off remarks by the movie characters? If they are part of British slang, do the names of the people change?