And on the sixth day the TV gods created entertainment! This spin on chapter one of the Book of Genesis was the publicity line for The Saturday Night Story, a 2015 ITV documentary. In one of the easiest TV scheduling decisions ever, it was run over two Saturday nights, offering a clips-and-quips history of the most significant peaktime of the week, especially for entertainment shows.

Although the viewing and distribution of TV have changed immeasurably across eight decades, there is a visible line from Variety, a 1947 Saturday-night show on the then solitary BBC Television Service, presented by Humphrey Lestocq, to today’s Michael ­McIntyre’s Big Show, 78 years later.

Both were part of a conscious – and paradoxical – attempt to make the most popular night for going out into the most tempting night to stay in. Lestocq (1919-84) – like many early TV presenters, an actor – also started another key part of Saturday broadcasting with the first live children’s show, Whirligig (BBC, 1950-56), beginning the tradition of TV giving exhausted or amorous parents a lie-in on the first morning without work or school.

Diurnal identification of the schedules had begun early on: among the very first offerings of BBC Radio were Friday Night Is Music Night (a title that still survives on BBC Radio 3) and Saturday Night on the Light, the final word a reference to the Light Programme, BBC Radio 2’s precursor.

However, at least until Sky Sports’ Monday Night Football (from 1992), which deliberately echoed the title of an American Football show created by ABC in 1970, the two television days most likely to be day-branded in the UK were Saturday and Sunday.

In the early decades, Saturday was the big entertainment night for the BBC, but Sunday fulfilled that role for ITV. This reflected, in different ways, Britain’s residual Christian heritage. Created by a Scottish Presbyterian, John Reith, and generally with at least one bishop on advisory committees, the BBC was careful about content on the Lord’s day.

The IBA also imposed some religious regulations on hours and programming, and the closure of shops on Sundays due to the same pious rules made Saturday nights less attractive to the advertisers on which commercial TV depended. Sunday primetime, however, could seed buying ideas for the reopening of the high street on Monday morning.

This meant that, when ITV launched in 1955 as the commercial competitor to the BBC, its first big weekend hit was Sunday Night at the London Palladium. It began with the comedian Tommy Trinder introdu­cing live turns, including the Lancastrian singer and movie star Gracie Fields and the American crooner Guy Mitchell. Set against that Palladium debut, the BBC showed its very ­different attitude to the seventh day by scheduling theatre, ballet and a spiritual pilgrimage.

Conversely, on the night before, the BBC wielded its heaviest pair of variety weapons – The Charlie Chester Show, fronted by a leading comedian of the era whose name was always prefixed by “Cheerful”, and a series entitled Saturday Night Out. The commercial network competed with Saturday Showtime, hosted by Harry Secombe of the Goons, but directed its biggest stars towards the Palladium show 24 hours later.

Despite ITV’s considerable efforts for understandable revenue-pursuing reasons, the UK taboo on Sunday as a fun day proved so strong that a 1986 attempt by Margaret Thatcher’s government to allow seven-day shopping – part of a wider deregulation that included TV – was rejected in the House of Commons; Sunday opening was eventually passed in 1994.

That continuing moralistic context may have made the God-fearing BBC even keener to sing and dance on Saturday nights. Saturday can equally be seen as the second of the three weekend nights, with some ITV networks constructed on that basis, most notably London Weekend Television (1968-2002).

For many years, a BBC specialism in Saturday primetime was the variety show built around a singer. In autumn 1971, The Harry Secombe Show set a format in which the host sang solo, introduced other singers performing their hits and then – to close the show – crooned a duet or trio with guests.

Successors included It’s Lulu and It’s Cliff Richard, cannily channelling performers associated with an annual BBC Saturday-night ratings-topper, The Eurovision Song Contest. These star ­vehicles popularised within TV the “shiny-floor shows”, based on set designers’ tendency to mix glitter into the studio stages. Shiny ceilings were often a feature too, thanks to a trend for dangling glitter balls.

Underlining the different rhythms of the two big British broadcasters, one giant of TV had become established since the 1950s as ITV’s “Mr Sunday Night” through his role as the most prominent host of Sunday Night at the London Palladium and then The Bruce Forsyth Show (ATV, 1965-69). The series that lured him to the BBC was The Generation Game, in which members of the public carried out silly challenges, often in fancy dress, to win as many prizes as they could remember as they trundled past on a conveyer belt.

Forsyth’s two spells on that show (1971-77 and 1990-94) – plus his late-career renaissance on Strictly Come Dancing (2004-15) and other sixth-day fare including You Bet! – added up to around a quarter-century of Saturday nights. However, the ­reason his run on The Generation Game was interrupted stands as a reminder of how treacherous this stretch of the schedules can be.

Bruce Forsyth’s Big Night (LWT, 1978) was an audacious attempt by Michael Grade, then LWT’s Director of Programmes, to challenge BBC dominance of Saturday night by building an entire evening around Forsyth, whose monologues and songs linked various game shows and comedy sketches. Though the presenter’s contract was worth millions in today’s terms, the ratings continued to be won by The Generation Game under its replacement presenter, Larry Grayson, strongly suggesting that, for all Forsyth’s considerable talent, the key to winning the night was more formats than performers. Seemingly accepting this, Forsyth returned to his conveyer belt.

His longevity on The Generation Game and then Strictly Come Dancing set a template for very long runs of Saturday hits. Yet, in years served, Noel Edmonds may even better Forsyth; he has the extra distinction of having flourished on Saturday mornings – with Multi­-Coloured Swap Shop (1976-82) – and evenings: Lucky Numbers (1978-79), The Late Late Breakfast Show (1982-86), Saturday Roadshow (1988-90), and then the pinnacle of Noel’s House Party (1991-99), in which he was notionally hosting a Saturday night at his country pile of Crinkley Bottom.

As acknowledged by the breakfast show reference in one title, these shows were an attempt to draw Edmonds’ audiences through his celebrity as a Radio 1 presenter. Indeed, his Saturday visibility was partly due to that being the only gap in his diary; during most of his BBC TV career, he was on the radio either Monday to Friday and/or Sundays. For TV historians, it’s striking that his biggest success – with House Party, a comically inventive format that has clearly influenced a time-slot successor, Michael McIntyre’s Big Show – came after the death of a participant in a stunt on The Late Late Breakfast Show. It seems unlikely that a presenter, executives or even network could survive such a tragedy today.

The only candidate for “Mrs Saturday Night” is Cilla Black, whose Blind Date (1985-2003) and Surprise Surprise (1984-2001, sometimes screened on Sundays) gave ITV two of its strongest weapons against BBC weekend domination as the easing of trading restrictions made both days increasingly significant for the broadcaster.

In this millennium, Saturday has largely been owned by two Geordie former child actors, with Ant & Dec’s Saturday Night Takeaway (2002-24) at least matching the popularity of The Generation Game and Noel’s House Party. Anthony McPartlin and Declan Donnelly are the clearest generic successors to Forsyth.

ITV executives and shareholders may note, though, that whereas Strictly has long flourished without Bruce (as did The Generation Game), Ant & Dec’s shows feel more umbilically attached to them, which may give the BBC a future weekend advantage.

While BBC Saturdays have generally meant entertainment, one drama series, Casualty, has been a fixture for decades – despite the irony of it being transmitted on the night that most patients and doctors consider the worst to visit A&E. The corporation was also clever in establishing early evening as a slot for family-friendly comedy: most notably ’Allo ’Allo! and Dad’s Army.

If the TV gods did create entertainment on the sixth day, then the devil – as many in British TV must see it – created streamers. Today the dominant television shows are attached to no particular day, except – for mega-fans and completists – the one on which Netflix or Disney+ drop them.

Yet terrestrial Saturday TV is still a thing, and the ghost of Humphrey Lestocq would recognise that Claudia Winkleman, Michael McIntyre and­ ­­Ant & Dec walk on the same floor that he did, shiny or otherwise.