to abandon or betray someone in order to protect or advance one’s own interests—originally (British politics, 1971) ‘to push someone under a bus’—derived from ‘to walk under a bus’ (British politics, 1966)
the exploitation and intimidation of tenants by unscrupulous landlords—UK, 1963—refers to Peter Rachman, a London landlord whose unscrupulous practices became notorious in the early 1960s
to exact the maximum payment which a person can afford—coined in 1918 by Eric Geddes with reference to the reparations exacted from Germany following WWI
In ‘hung parliament’, ‘hung’ means ‘in which no political party has an overall majority’ – cf. the US expression ‘hung jury’, where ‘hung’ means ‘unable to decide’.