The Great British Bake Off
Year launched: 2010
Countries shown in: 12
It's massive in: Scandinavia. The Swedish, Norwegian and Danish versions are huge. In Denmark it's called Den Store Bagedyst (The Great Baking Joust).
Who made it first? Love Productions / BBC Worldwide
Why it works: Floury Liverpudlian hunkster meets loveable grandma figure, with Mel'n'Sue watching on as hapless celebrities or ordinary people utterly fail to understand how ovens work.
Come Dine with Me
Year launched: 2005
Countries shown in: 36 (including Iran, obviously)
It's massive in: Canada. It's the highest-rated lifestyle show there.
Who made it first? ITV Studios
Why it works: It's the cheapest TV format known to mankind. You film it in people's houses, they buy the food and provide all the props and dialogue, while all you do is pay for a taxi and a measly £1,000 prize money. Result.
p.s. I'd expect it from Jodie Marsh, but does Debbie McGee really have that many tattoos?
Masterchef
Year launched: 1990 with Lloyd Grossman, but rebooted with Greg'n'John in 2005
Countries shown in: 35
It's massive in: Australia. While a weekly show is enough for most countries, the Aussie version is shown six nights a week from Sunday to Friday.
Who made it? Shine Television (Elisabeth Murdoch's company) / BBC Worldwide.
Why it works: People love cooking, people TV; people love cooking on TV especially when it involves the ritual humiliation of a contestant whose daring mustard-flavoured ice cream crab cakes almost made Gregg Wallace vomit.
Strictly Come Dancing
Year launched: 2004
Countries shown in: 43. There have been 200 separate seasons shown globally, mostly called Dancing with the Stars.
It's massive in: India. The Hindi-language version, Jhalak Dikhhla Jaa, is in its sixth year and reaches 100 million people per season.
Who first made it first? BBC
Why does it work: Just when you thought celebrities couldn't get any better, they start dancing.
Pop Idol
Year launched: 2001
Countries shown in: 46, including some global regions
It's massive in: Pretty much everywhere but particularly the USA, where it's been the no.1 most-watched TV show for nine years
Who first made it? Fremantle Media and Simon Fuller's 19 Entertainment.
Why it works: The early rounds of mocking people with mental health problems gives way to a soap opera format to the audience goes on a "journey" with the would-be stars, feeling ownership of their glory/failure.