There are more than a few awkward moments in the official accounts of Britain's glorious history. For example, we have always loved our royal family - but we were also the first country in Europe to embrace the act of regicide, in 1649. And our empire was a force for peace and civilisation in the world, for which our subjects were eternally thankful - until they ungratefully rose up and turfed us out.
Another of these awkward moments was when beloved wartime leader Winston Churchill was defeated resoundingly in the 1945 general election, which took place just months after the end of the barbarism of the Second World War.
So why did voters flock to the polls in such huge numbers to evict History's Greatest Briton from Downing Street? Hadn't he just won a war for them?
Ken Loach's new film - a documentary this time - explores this and other issues arising from the resounding demand for change in 1945. It brings together footage from the time, in the form of newsreels, election broadcasts and so on, with the stories of those who lived through it, told in their own words.
We hear from dock workers, nurses, miners and others. Loach can always be relied on to offer a gritty portrayal of working class life, but this time all he does is allow people to talk about their own lives.
Labour under Clement Attlee stormed into government in 1945 with a programme of mass nationalisation, the creation of a national health service, extensive house building and a whole host of radical moves which would make a Blairite of today choke on their champagne breakfast.
The interviewees give powerful stories about their lives as children, sleeping five to a bed (and that doesn't include the vermin), seeing their friends die of illness, and losing their families in the war.
The Attlee government does not escape criticism. Despite its radical legislation, it was all done on behalf of the working class, rather than giving workers any power themselves. The same old bosses often returned, but now exploiting workers in a nationalised company instead.
After giving a run-down of the following few decades, Loach leaps forward to 1979 and the class warrior who, more than anyone else, represented the destruction of this project - Margaret Thatcher.
The Spirit of '45 gives a timely reminder that it has not always been "common sense" to let the private sector run our public services, to curb trade union power or to cut benefits to encourage people to work.
This isn't Michael Moore, but it's not supposed to be. The film is shot in black and white and hasn't become distracted with trendy production techniques. Loach himself, who conducts the interviews, is always out of shot and never heard. But even without talking, the veteran left wing director can make a very powerful argument.
The Spirit of '45 is directed by Ken Loach and released on 15 March