"What if the Nazis had won the war?"
That's the question that the BBC's counterfactual period drama SS-GB seeks to tackle in a big-budget adaptation of the 1978 Len Deighton novel, featuring swastikas draped over Parliament and tanks in Trafalgar Square.
But it is far from the first time we have seen fictional Nazis marching the streets of London and taking over the world.
If SS-GB has given you a taste for dystopian alternative histories of the Second World War, here are some more TV dramas and films to try:
The Man in the High Castle
Let's start with the most obvious comparison: The Man in the High Castle, adapted from sci-fi author Philip K Dick's 1962 novel and now heading for its third season on Amazon Prime Video.
The alternative history drama is set in America, which has been conquered and partitioned. The two new world superpowers are the Greater Nazi Reich and the Japanese Pacific States. Day-to-day life in the US is very different and fraught with new dangers.
Like SS-GB, it answers the question: what would life be like if the Axis powers had won the war and imposed totalitarianism on their foreign enemies? But The Man in the High Castle is also a vastly different story: where SS-GB is a police procedural set shortly after defeat in 1941, this drama takes place fifteen years later when the new order is fully entrenched.
Robert Harris's novel became an American HBO film in 1994, starring Rutger Hauer, Miranda Richardson, Jean Marsh and Peter Vaughan.
It is 20 years since Germany conquered Europe, turning the continent into Germania, and the war with the Soviet Union rages on. Adolf Hitler is still in power at the age of 75, and President Kennedy is preparing to restore diplomatic relations with Germany. News of the Holocaust has been kept a secret for decades.
At this key political moment, an American journalist and an SS detective uncover information which could topple the Third Reich.
Season three of Misfits sees the gang thrown into an alternative timeline where the Nazis conquered Britain. It all went wrong when an old Jewish man, Friedrich, tried to use Curtis's time-rewind superpower to go back and kill Hitler – but it didn't go according to plan.
Disastrously, the Nazis try to force Seth to give them their own superpowers while Misfits find themselves in the resistance, fighting back.
It Happened Here
This 1960s film reveals an alternative history in which the UK has been invaded and occupied by Nazi Germany. People are divided over whether to resist or collaborate, but trapped in the middle is an Irish nurse working in England. It Happened Here was made on a shoestring and was a largely amateur production, but won praise for being both compelling and believable. What happens to all the ordinary people just trying to survive?
An Englishman's Castle
Peter Ingram (Kenneth More) is a writer for the hugely popular soap opera An Englishman's Castle, but what he doesn't realise is that his country is run by a collaborationist fascist government – and his programme helps prop up a vision of normality.
In this 1978 BBC television serial (available on DVD), Ingram's period drama is set in London in 1940 during an imagined German invasion and occupation. But Ingram is oblivious to the reality that the Nazis are actually ruling his country, behind a facade of normal English daily life. German rule is maintained through a system of collaborators and secret torture chambers. Gradually, Ingram cottons on to the what's truly going on – and must decide what to do.
Jackboots on Whitehall
With a little more humour than most of the programmes on this list, Jackboots on Whitehall is a Second World War spoof set in an alternative history where Nazi Germany has seized London by drilling under the Channel and coming up through the cobblestones in Westminster.
How will the Brits fight back? In this 2010 model puppet adult animated satirical comedy action war adventure film (try saying that fast), they band together at Hadrian's Wall to thwart the German invasion. The movie features voice acting from Ewan McGregor, Rosamund Pike, Richard E Grant, Timothy Spall, Richard O'Brien and Richard Griffiths.
The Other Man
If you can track down a copy of this one let us know, because it sounds amazing. The Other Man aired on ITV in 1964 and starred a young Michael Caine as army officer George Grant. Britain has capitulated to Germany in 1940 to avoid bombing, but – as in SS-GB – Nazi rule brings a slow creep of totalitarianism and fascism. Grant becomes complicit as the new rulers ensure the reconquest of India, racial atrocities, and the building of a Channel tunnel using slave labour.
At the end, Caine's character is made unwilling "hero of the Reich" when he is attacked by the Cossacks. But when he regains consciousness, he finds he has been rebuilt using advanced transplant surgery using parts from "live donors".
SS-GB airs on Sundays at 9pm on BBC1