Surely the last 80 years at least?
When I think of UK governments since the war, I can think of a whole list of things Labour governments have done to improve people’s lives. The 1945 government establishing the NHS, strengthening the welfare state, massive house building programme (ok that peaked just after they left office, but the programme was Labour’s); the 60s and 70s Labour governments’ huge extension of education, not only many new universities, but also the introduction of comprehensive education, and of course extension of social justice and equality, the equal pay act, etc; the Blair/Brown years not so radical, but some important reforms like the independence of the Bank of England, introduction of the minimum wage, etc…
ButTory governments? All Churchill’s achievements were with the wartime cross party government - as Tory PM in the early 50s he did nothing (partly of course because he wasn’t there for much of it); Eden? - the Suez crisis; Macmillan, Douglas-Home? - well can you think of anything positive? Heath - joining the EU, the one Tory highlight; Thatcher - total disaster from which the UK has never recovered; Major - Black Wednesday; Cameron, May, Johnson, Truss…