What are the biggest what it's in Tv history?

[Meaty]

For example
what if coronation street hadn't been commissioned , would emmerdale hollyoaks and eastenders have started?

[TubThumper]

Big Brother.

I guess it was the first modern reality show which gave way to a global reality television boom. Without it, you probably would have had I’m a Celebrity… Get me out of here, Survivor, Love Island and Traitors.

[Arran]

My theory is that Children's BBC would not have existed without Children's ITV.

Children's ITV was created to fulfil a purpose - a national on-screen brand and a unified output in a fragmented regionalised TV network.

The weekday afternoon children's programmes on BBC1 were broadcast nationally most of the time with occasional regional opt-outs in Wales and Scotland, and the BBC in itself was deemed a strong national brand, despite there being on-screen brands for schools programmes (BBC Schools) and pre-school programmes (See Saw) before Children's BBC (and ITV) was launched.

[George 1978]

It's difficult to speculate something which probably would never have happened, but what I do know is that the terrestrial TV schedules would have more variety and choice as it did in the 1970s and 1980s, and I think that the increase in episodes of soap operas have diluted the quality of the way other genres of programming are made. William Roache for one, probably couldn't imagine a life without Coronation Street's existence; it is his bread and butter and very much a "right place, right time" thing for him. The Eurovision Song Contest is in four weeks' time, and it is arguable that without the success of the show over the decades, one could argue that we wouldn't have had ABBA without Eurovision; the same with the Brotherhood of Man; Riverdance in the interval; and even, dare I say it, Cheryl Baker. That is a fine example which has been going for decades, long before Pop Idol or Popstars or any of those shows.

Children's BBC probably wouldn't have existed without long-standing programmes like Blue Peter; Play School and Grange Hill; they flew the flag of children's TV on the BBC long enough to merit such umbrella branding, and I suppose that, as Arran has said above, Children's ITV was first and so that influenced Children's BBC, and it is arguable that they probably wouldn't have done that in 1985 if ITV had not done something similar two years earlier.

[George 1978]

For example
what if coronation street hadn't been commissioned , would emmerdale hollyoaks and eastenders have started?

Also, I think that from the 1980s onwards, the ratings issues for Coronation Street were such a huge thing (advertising revenue and all that) was the reason why the BBC fought back with that EastEnders thing that they launched. The problem is that the number of episodes increased in the late 1980s and 1990s felt to me like bidding in an auction, almost ignoring anyone and anything do with other genres of programming. Emmerdale (Farm) was launched in 1972 as an afternoon serial many years before this. I would like to assume that what you said would have happened if Coronation Street had not been commissioned. But it is like asking whether World in Action would have existed if Panorama had not been commissioned. If things were the same as the 1980s such as two episodes a week now, that would be a lot better.