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Opportunity Knocks? Trust, technology and television

Published: 7 September 2020

From 1950s clapometers to televised lottery draws, TV entertainment is built on technology that audiences have to trust—but how does it work?

The history of reality TV, talent contests and quiz shows is full of notorious gaffes and scandals over accusations of cheating or producer interference. Let’s take a look at some objects from our collection that reveal how viewers engage with the small screen—and whether we can trust what we see.

The Clapometer: measuring audience reactions

Presenter Hughie Green on Opportunity Knocks
Presenter Hughie Green on Opportunity Knocks

The broadcast talent contest Opportunity Knocks began on the radio in 1949, and made its television debut on the fledgling ITV network in 1956.

The format was simple: variety acts of all kinds would perform in front of a live studio audience, and a public vote would decide which of the episode’s acts would move forward into the final.

Presenter Hughie Green gave viewers the address for them to post in their votes—it was some years before telephone voting would become the norm. That meant viewers at home had to wait until the next episode to discover if they had wasted a postcard or not.

To give a bit of excitement and visual flair during the broadcast, the producers introduced a nifty bit of technology called the ‘clapometer’. The clapometer measured the strength of the applause in the studio, which viewers would see on a moving dial on the screen.

Hughie Green’s Clapometer (Audience Reaction Indicator), used on Opportunity Knocks, 1956–78
Science Museum Group Collection More information

Cynics might assume that the clapometer was rigged. If the producers had a favourite performer, they could sway the public vote by suggesting the audience reaction was more favourable. However, in our collection we have the actual kit called ‘Hughie Green’s Clapometer’. It’s a hinged wooden box containing valves, dials and wires, with a sticker on the front identifying it as an ‘Audience Reaction Indicator’.

We can’t tell for sure how accurate it was—or if it actually worked—but if it is a glorified prop, it’s very convincing.

Interior of Clapometer Science Museum Group Collection
Interior of Hughie Green’s clapometer

The Mastermind buzzer: timing the quiz

There are few TV catchphrases more memorable than ‘I’ve started so I’ll finish’. Coined by Mastermind presenter Magnus Magnusson, the phrase is uttered if the buzzer sounds half-way through a question at the end of a round.

In our collection is an original buzzer (or tone generator) used on Mastermind in the 1970s. It looks fairly nondescript—a small metal box with a red button. What this button reveals, however, is that the buzzer was human-operated, meaning someone had to be keeping track of the time to make sure that the notoriously difficult quiz show was fair to all contestants.

Mastermind tone generator, 1970s BBC Heritage Collection/Science Museum Group Collection
Mastermind tone generator, 1970s

Guinevere: televising the National Lottery draw

One of the most recognisable objects on display in the Science Museum in London is Guinevere, the 1990s National Lottery random ball dispenser. It was donated by Camelot Group, who still hold the franchise for the National Lottery in the UK.

‘Guinevere’, Random Number Selector, used for drawing the British National Lottery, 1994
Science Museum Group Collection/Camelot Group PLC/National Lottery Commission More information
Guinevere name plaque Science Museum Group Collection/Camelot Group PLC/National Lottery Commission
Detail of ‘Guinevere’ name plaque

The first National Lottery live television draw was aired on BBC One on 19 November 1994, sandwiched between Bruce Forsyth’s The Generation Game and the long-running medical drama Casualty. National Lottery players bought and registered their tickets at shops, garages and post offices—it was some years later that scratch cards were introduced.

Hosted by Noel Edmonds, the hour-long programme included a contest to decide which audience member would ‘release those big money balls’. Guinevere was not the machine used in the first National Lottery draw—that was an identical machine named Merlin.

The first broadcast included footage of diligent Lottery workers at their headquarters. It was obvious that instilling public trust was paramount, so every part of Guinevere that the balls travelled through was clear plastic. Even the set of balls used was determined by an audience member picking an envelope.

The draw master (wearing white gloves) started the machine, before handing the attached controller to the audience member to start the balls rolling. The balls themselves were lined up in clear plastic chutes, and at the press of a button they were released into the central drum. Every few seconds a ball would drop out of the bottom of the machine and roll into a line for the presenter to read out. The dispensers used in the live television draws were remarkably robust, with very few incidents of malfunctions on air.

Operational buttons of ‘Guinevere’ Random Number Selector Science Museum Group Collection/Camelot Group PLC/National Lottery Commission
Operational buttons of ‘Guinevere’ Random Number Selector

TV licence detector vans: Watching the watchers

While TV audiences have to trust what they see on screen, the television industry needs to trust that their audiences are watching legally. Nowadays the television licence required to watch live broadcasting is collected and enforced by the BBC through the TV Licensing Authority, but it was previously overseen by the General Post Office.

Post Office Television Detector Van Science Museum Group Collection Image source
Post Office Television Detector Van, 1959–63

Since the 1950s, the authorities have used television detector vans containing equipment to detect whether a household within range of the vehicle has a working television set. One such van in our collection is this blue vehicle, used in Northern Ireland in the early 1960s.

Neither the BBC nor the Post Office would reveal much information about how the vans worked, but while they were secretive on the science, they were not subtle with their surveillance. The van clearly states that it is a ‘television detector’ and boasts a large yellow and black antenna on the roof.

Interior of Post Office Television Detector Van Science Museum Group Collection
Interior of Post Office Television Detector Van

Whether or not the van worked well as a detector, it was clearly designed to act as a deterrent to anyone looking to watch television without paying for a licence. At the time there were over 12 million television licences issued in the UK, and the cost of the licence was £4. The BBC’s funds depended on viewers paying their licence fee, so there was a lot to gain from using television detector vans—if the public believed they worked.

TV, technology and fair play in the 21st century

These objects from behind the scenes of television production and viewing tell us a lot about the importance of trust in entertainment. High-stakes programming like the National Lottery draw depends on viewers believing the process is fair. And with public service broadcasting dependent on licence fee income, the TV Licensing Authority still uses a variety of tactics to deter watching without a licence.

Would we be convinced by Hughie Green’s clapometer today? The rise of technology like telephone and text voting, as well as the development of reality TV formats, has had an impact on how we watch. But trust is still central, and accusations of cheating or foul play can still sink a contestant’s popularity or tarnish a show’s reputation.

Further reading