Marking the BBC's one hundredth birthday, Sandi Toksvig and regular panellist Alan Davies are joined by Zoe Lyons, Greg James, Richard Osman and extra special guest Basil Brush.

Themes

- The panel's buzzers are all TV show themes. Greg has Grandstand, Zoe has Ski Sunday, Richard has Wimbledon, and Alan has Teletubbies. Alan was expecting the theme to Jonathan Creek, and says that he once shopping and had to stop himself singing the tune, for fear people would complain about him singing his own theme tune.

Topics

- The person who has spent more time on television than anyone else in the world is Carole Hersee, the girl who was on the BBC test card. It has been estimated she has been on TV for over 70,000, which is eight continuous years. Carole is in the studio with the clown doll Bubbles, which was a kit that Carole herself made. Her father, George, was a BBC engineer who was helping to design the test cards, and it was decided that a child would be better than an adult as there would be no fashion or make-up to worry about. George sent in pictures of Carole and her sister to a committee and it was decided to stick with these kids. Carole has not been given a Guinness World Record for her achievement because it is not achievable to be beaten. Carole went onto work as a period costume designer for the stage. (Forfeit: Richard)

- The BBC sent people to sleep by having a one-hour long break. The Toddlers' Truce was a time between 1946-57 when there was no TV in Britain at all between 6pm-7pm so parents could their children to bed. It worked well until 1955, when ITV launched and they filled that time to get more advertising revenue. The Truce was ended after much Parliament wrangling in February 1957. (Forfeit: The Shipping Forecast)

- XL Tangent: The BBC sends out a signal with the pips that set you Economy 7 heating working. There is a frequency with the pips at midnight that turns it on called the Radio Teleswitch.

- Tangent: When Sandi was a child her father was a broadcaster in Denmark. TV would start at 7pm, and he would read the news, often doing it while smoking a pipe, and with a telephone next to him as there were no filmed inserts. This lasted an hour, and was followed by a half-hour long documentary, then the entire service would shut down. Thus, Sandi's father was two-thirds of all Danish TV.

- XL Tangent: There is an online channel called Napflix which is designed for people to sleep to. It began in Spain, and programmes on it include a two-part documentary on the history of Scalextric, a film entitled "The New York Subway Journey", and footage of an oscillating fan.

- The thing you can get on the Blue Peter black market are the badges. The first Blue Peter badge was awarded on 17th June 1963, and it is probably the world's longest-running family discount scheme, with the badges allowing you free access to over 200 UK attractions. As a result of this, for a brief period in 2006, the badges had to be temporarily suspended after an online black market had been discovered selling the badges. A leader in The Times described the black market as: "a knife to the national psyche". In order to use your badge, you need an accompanying ID card as well, and today there is a detailed card index of every child that has been given a badge. Greg has two badges due to him making multiple appearances on the show.

- Tangent: The original producer of Blue Peter, "the legendary" Biddy Baxter, as a child wrote twice to Enid Blyton, and both replies were exactly the same. This made Baxter so angry that she made sure that every child who wrote to the show got an individual response, which is still practiced to this day.

- XL Tangent: Greg appeared on "Blue Peter" because he broke the World Record for playing the most toots on a party blower. The original "Blue Peter" was a blue flag with a white square in the middle, which means that a ship is about to leave port.

- Tangent: One of the most famous things made on Blue Peter was a model of Tracy Island from Thunderbirds. The panel are shown one made by Anthea Turner in 1993, which she still has. Alan's children watch the modern animated Thunderbirds, then Alan showed them some of the original episodes, and his kids were astonished by how slow everything took to do.

- XL Tangent: When Richard ran Endemol, every year they would send interns to the BFI archive to watch lots of TV entertainment shows from the 1970s and 80s. Every intern would come back and say: "That was literally the most boring day ever!"

- Tangent: Petra, the first-ever pet on Blue Peter, was an imposter. Just before Christmas 1962, Petra was tiny mongrel puppy that was introduced to the show, but her first appearance was also her last as she died of a viral disease two days later, so the producers raced around London trying to find a dog that looked like Petra. They found one in a pet shop in Lewisham, and that became the new Petra. Richard claims he had the exact same thing with Alexander Armstrong.

- Sandi introduces a special guest to the show: Basil Brush, who asks the panel where do most urban foxes eat. Urban foxes are not fussy eaters, and will eat rodents, worms, birds, rabbits, fruit and berries. (Forfeit: My bins)

- XL: The person who made a fortune from the invention of television is not the man normally credited for inventing it. While John Logie Baird invented TV in 1926, he didn't get any success from it. In 1906, he was bullied at Glasgow Technical College because he had very bad eyesight by John Reith, later Lord Reith the first Director-General of the BBC. Baird did invent anti-rust razors, but they were made out of glass and shattered easily; pneumatic shoes that inflated like balloons for people with flat feet; and a homemade recipe for haemorrhoid cream. His only big commercial success was socks that you wore under your normal socks. Baird had poor circulation, meaning he had very cold feet, so he made socks powered with the antifungal medicine borax, which kept your warmer and cleaner. These socks were popular with soldiers in the trenches of the First World War, and the money raised from the sale of them helped fund Baird's TV research. The world's first working TV set was made from an old hatbox, a pair of scissors, darning needles, bicycle light lenses, a used tea chest, wax and glue. There was a disc in the TV which had different lenses in it which would rotate, each lens scanning a different part of the subject, reflecting light to a receiver. (Forfeit: John Logie Baird)

- XL: John Logie Baird invented television in the Santa Cruz Valley in Trinidad and Tobago. Baird moved there in 1919, and to make money to fund his TV experiments he started a jam factory. It failed because the factory was besieged by insects, but it was there where he made his first TV prototypes. Baird demonstrated the very first black-and-white TV in the world in 1926, the first colour TV in 1928, and later infrared TV, transatlantic broadcasting and 3D TV. (Forfeit: Scotland)

- XL Tangent: The other person to have a strong claim to inventing TV was the American Philo Farnsworth. He independently came up with the idea in a chemistry class at the age of 15. His electronic version worked better than Baird's mechanical TV. There was a patent dispute to say that Farnsworth could not possibly have invented the TV, but Farnsworth old chemistry teacher found the drawings he had done when he was 15, and Farnsworth won.

- The person who bought nine apartments just to fill them with their own TV shows was Marion Stokes. Born in Philadelphia in 1929, she inadvertently collected the only comprehensive archive of American TV news from the late 1970s to 2012. She began on 4th November 1979, with the Iran hostage crisis, recording the news on a VCR. Her son claimed that she hit record and it never stopped. She chronicled Fox, MSNBC, CNN, C-Span, CNBC and all of it became a family obsession. They would have to interrupt dinner to change the tapes. She filled 71,000 VHS and Betamax tapes, containing every minute of US TV news between 1979 and 2012, when she died. Stokes had to buy nine apartments to store all the tapes in, making the money by being an early investor in Apple.

- Tangent: Sandi once owned a dog called Bompy who would shag anything. Sandi was once visiting the home of the founder of the Born Free Foundation, and Bompy shagged the VCR machine.

- XL Tangent: On Twitter, Richard once question how Frasier, in the US sitcom of the same name, managers to have the incredible apartment he has. One of the writers, Joe Heenan, came back to Richard says that all the writers had sort of assumed that he had invested very early in Apple, because as a host on a local radio show he should not have that much money, to which Greg replies: "Excuse me?"

- XL Tangent: Pre-digital, all TV networks constantly taped over stuff and wiped discs in order to save money. Perhaps the most significant loss is the loss of the film of the Apollo 11 moon landing. The images beamed back from the moon were high-quality, but converting them for TV was complicated, and thus the footage was degraded. NASA did tape a raw high-quality tape for future use, but then lost track of it. One of the only surviving pieces of evidence of the footage is a still image of a screen displaying the much cleaner picture. The panel are show a crisp photo of an astronaut - or rather Sandi's father wearing an astronaut.

- The thing dogs like to watch on TV is anything with a high-enough frame rate. Humans need a minimum of 16-20 frames per second in order to perceive what we think of as a continuous film. Dogs however need about 70 frames, so a film of 24-25 frames to a dog is like a series of flickering images. However, in recent years, frame rates have increased on TV, so sports programmes are now up to 60 frames per second. However, people think of the original 24-25 frame rate as classier. (Forfeit: The Great British Bake Off; Have I Got Chews For You; The Chase)

- XL Tangent: Soap operas started in the USA on daytime radio, and are so called because they advertised soap in-between segments. Procter & Gamble had set up their own recording studio to produce their own shows. The mother of all soap operas is "Oxydol's Own Ma Perkins", a US radio show sponsored by a laundry soap starring an actress named Virginia Payne. In the story, her character, Ma Perkins, ran a lumberyard. The show ran from 1933-60 and Payne played Ma Perkins in over 7,000 episodes.

- XL Tangent: The BBC held out against soap operas because they thought they were crass. In 1941, they launched a show called "Front Line Family" on the radio in order to try and persuade the Americans to join the war. It was broadcast on the BBC North American Service, and the idea was to see an ordinary family in wartime conditions, with people dealing with Blitz, rationing, men going off to war and so on. One BBC executive wrote; "What we are trying to do is to drag America into the war." The show was a huge success. The most famous radio soap opera is "The Archers", which began in 1951. June Spencer, who played Peggy in the 1950 pilot, is still playing the character today, at the age of 102 at the time of recording.

- The morally dubious activity that takes place while people are watching TV is skipping adverts. In 2002, the head of Turner Broadcasting System, Jamie Kellner, accused TV viewers who ignored or fast-forwarded through ad breaks of being immoral. He claimed that the contact you make with the network is to watch the ads, because if you do not then you are stealing from the programme. Kellner did say that a certain amount of tolerance is allowed for going to the bathroom, but only if you really need to go.

- XL Tangent: "Seinfeld" is so much short than it used to be because it is played at a faster speed. Executives worked out that they could more commercials in if the show played faster. Thus, since 2014, repeats have been speeding up by 7.5%, in comparison to the original broadcast shows, giving an extra two minutes of ad space. The commercial half-and-hour which used to be 25 minutes is now 19 minutes.

- Tangent: The BBC has never carried advertising, but it still needed programme breaks, so they used "interlude films", such as the Potter's Wheel, and they also have idents or moving logos. This included the moving bat wings logo, which were made out of proper physical objects that moved. The bat wings model was so delicate that it only lasted for as long as it was filmed, then it completely collapsed. On set are three other models used for idents, namely the BBC One spinning globe, the BBC Two clock, and the BBC Two moving lines.

General Ignorance

- XL: The first BBC TV broadcast was at 3pm on 2nd November 1936, and their first repeat was on the same day. The first broadcast was called [i]Opening Night and featured speeches from BBC and government officials, and then a few variety acts, all transmitted live. However, there were two competing TV systems at the time: Baird's mechanical system, and Marconi's system which was watched via a tilted mirror. A coin toss was used to decide which would air first, with Baird winning. After Baird's broadcast, there was a very brief pause, the entire cast and crew switched studios, and the same programme was repeated in the evening on Marconi's system. (Forfeit: The next day)

- The world's longest-running TV show is the Lord Mayor's Show from London. The parade is over 800 years old, originating in the 13th century. The BBC began televising it in 1937, and it has been broadcast every year since, apart from World War II. Thus, there have been 77 instalments over a period of 85 years. (Forfeit: Coronation Street)

- Tangent: When horse racing was televised they used to fit a camera to a Citroen which drove along with the race to film it.

- Most radiation has no colour. When radiation is commonly depicted as green in popular culture, most of it is invisible. There is Cherenkov radiation which is seen in water-cooled nuclear systems, but it makes water glow blue. (Forfeit: Green)

- XL Tangent: The reason why many people think radiation is green is because of its use on radium dial watches. As a child, Sandi and her brother spent a lot of time living in hotels, and they played a game between themselves called the sock game. They turned the lights out, rolled up a pair of socks, and throw the socks at each other. If you hit the other person, you got a point. Sandi always won, and on her brother's 50th birthday, she revealed the reason why she always won was because she could see his luminous watch dial.

Scores

- Richard Osman: -4 points
- Zoe Lyons: No score given.
- Alan Davies: -15 points
- Greg James: -19 points
- Basil Brush: -20 points