The job interview was hardly orthodox: two men on their knees at an enormous model railway layout in Broadcasting House, London. The year was 1958, and the train set was a permanent fixture in the office of John Hunter Blair, a producer at the BBC.
This was Hunter Blair's way of taking stock of Christopher Trace, a former actor, who was up for the job of co-presenter of a new weekly television programme for children.
Trace must have given the right signals. On October 16 of that year, he introduced the first programme beside Leila Williams, a former Miss Great Britain. The pair could never have imagined that the programme would go on to become a national institution.
Its name was Blue Peter, and next Friday, after 3,150 shows, it celebrates its 40th birthday.
The Blue Peter is the flag hoisted when a vessel leaves port - hence the programme's enduring galleon motif, which is meant to convey a sense of adventure and crew-like togetherness. Half a lifetime on, Blue Peter takes up a large part of that corner of the nation's heart reserved for the most cherished television memories. For confirmation, just ask almost anybody who has grown up in Britain over the last four decades. Out tumble the names of the changing ship's company - Lesley Judd, John Noakes, Valerie Singleton from those who watched in the Sixties and Seventies; Diane-Louise Jordan, Caron Keating and Richard Bacon from the younger set.
Then there are the resident pets, Petra, Shep and Jason among them. And, of course, the signature phrases: Get down, Shep, sticky-backed plastic and here's one I made earlier - the last two forever associated with the hand-made toys, gadgets and other do-it-yourself efforts called "makes", which were designed to save cash and foster creativity.
The programme's producer and editor for 27 years was the legendary Biddy Baxter. She decided early on that viewers should feel themselves a part of things and introduced the famous Blue Peter badges. "We decided that these should not just be given away, but earned. So anything good - an interesting letter, a story, an idea, a drawing - got a badge. Over time, we could tell from viewers' letters that we'd built up a great rapport with the audience."
But not all were from children, and not all were complimentary. "Filthy," was how one mother described the search for a suitable mate for Petra. Another parent complained to the BBC in 1965 of the obscenity of showing Petra suckling her pups. The production team pointed out that the animals were there to help children learn the facts of life - that is, sex, birth and death. Pretty progressive stuff in the Sixties.
The Seventies growth in eco-awareness led to regular items on the environment, while frequent appeals for causes both at home and abroad were often hugely successful. The best remembered is the 1979 Appeal for Cambodia, which netted nearly pound;4 million from thousands of bring-and-buy sales held around the country.
Rather than money, the appeals asked children to send tradeable oddments such as milk bottle tops, rags and stamps because the guiding principle behind the appeals is inclusiveness. Less privileged children should have the same chance to help others as those more fortunate .
Blue Peter was sometimes criticised and occasionally even derided for its appeals. Critics panned its scout-hut sincerity and detected a Blytonesque, middle-class air. It's a charge that irks some of the programme's most famous names.
John Noakes, still with his trademark rugby league accent, scoffs at the notion of middle-class bias. "Not with our audiences. All the dockers and shift workers knew us. We got letters from everybody, so I don't think of it in class terms at all."
And Valerie Singleton, one of the first presenters, seems more worried at having been labelled "Auntie Val" "None of the other girls was called 'Auntie' - why just me?" Singleton and Noakes still chuckle over near-disasters: Lulu, the uncontrollable and incontinent baby elephant, the electric camp fire that suddenly became a real one in a studio filled with Girl Guides. Funny, yes, but sometimes stressful. And, says Singleton, pretty thankless. "The BBC never really valued presenters, never gave them the praise they deserved. It would have been nice if they'd just said, every so often, 'Gosh, that was great. You really do a bloody good job'."
What made the job most worthwhile, she says, was viewer enthusiasm and the camaraderie of the presenters. Judging by their on-screen sparkle, the current gang of four - Richard Bacon, Katy Hill, Konnie Huq and Stuart Miles - get on just as well as their predecessors. But the job carries big responsibilities. Huq, a Cambridge graduate and the programme's most recent recruit, recognises that she is expected to set an example to her young fans: "You have to be an upright member of society, to behave yourself inside and outside the studio."
The Blue Peter tradition is of youthful exuberance joined with unforced good manners, curiosity and compassion, all qualities apparent in the filmed reports from Mexico, the site of the programme's most recent summer expedition. Along with the fun elements - a singalong to Mexican bands, a hair-raising rollercoaster ride - there was an exploration of Aztec historical sites and a moving report from Huq on young children forced to live on the streets.
Current editor Oliver Macfarlane says the style has changed somewhat - faster cutting, more exciting visuals, less restrained presenters - but the substance hasn't. "We still try to avoid plugging things like toys and other consumer goods, and we concentrate on topics that we feel young viewers will simply find interesting in themselves."
According to the ratings, the mix is still spot on. Blue Peter regularly tops the charts for children's programmes, its postbag still brims and the Blue Peter Web site is one of the BBC's most visited.
But how long can such an ideal survive in a world of multi-channel television, much of it run on purely commercial lines? Macfarlane pins his hopes on Blue Peter's distinctiveness and the belief that changing times will bring changed expectations. "Audience size will be judged by what is considered acceptable in the new climate. Economic pressure from audience fragmentation is a fact of life. Like everyone else in the BBC, we'll have to cope."
'Blue Peter Night', BBC2 Saturday October 10, from 6pm, will include classic clips, including Lulu the baby elephant, as well as profiles, retrospectives and a celebrity cast.'Blue Peter', BBC1, Friday October 16, 5.10pm, will be a bumper birthday party in the TVstudio
It was like school, wasn't it? But on television - with a lot of sticky-backed plastic."
Paul Whitehouse, comic
"Some people want a big house in the country, and a fancy yacht, and holidays in the Seychelles every year. All I ever wanted was a 'Blue Peter' badge, and I never got one."
Cheryl Baker, TV presenter
"I always felt the appeals were very focused and a lot of thought had been put into them. And they really did it in a way that wasn't condescending - you were told the proper story and you had to make your own mind up."
Kevin Keegan, manager Fulham Football Club
"At school you were either a 'Blue Peter' viewer or a 'Magpie' viewer, and there was an intense rivalry between the two. Of course, Magpie was rubbish, and the reason was because they didn't have John Noakes, and he was God at the time. Valerie Singleton was always a bit 'matrony' - you quite liked her but you never really fancied her. At that age you never really fancied anybody, you just wanted to be John Noakes."
Simon Mayo, disc-jockey
"When I was about three years old, I used to sit and watch 'Blue Peter' all the time and pretended that I was one of the presenters. I loved it, I never missed it."
Gaby Roslin, TV presenter
"I could immediately identify with John Noakes. He was from Halifax, which was just over the hill from us in Rochdale and he spoke my kind of language. He was a bit like an exotic, adventurous older brother."
Mike Oldfield, musician
40 years of Blue Peter appeals have raised the following: * Vehicles
15 lifeboats; 57 lorries; 10 trucks; 4 buses; 3 caravans; 102 wheelchairs and six cars * Livestock
400 oxen; 13 guide dogs and 32 ponies (for riding for the disabled) * New buildings
9 specially furnished flats; 1 log cabin; 12 houses; one indoor riding school; 16 tack rooms; one nursery and training centre; two old people's centres; 6 bungalows * Third world food and medical aid
A total of pound;13,596,745 was raised which was divided betweenclean drinking water systems in India, Pakistan and Bangladesh; Brazilian leprosy victims; Romanian orphanages; mobile eye units in Africa and economic assistance for 150,000 people in 21 other countries; 100,000 doses of vaccine It is estimated that mobile eye units saved the sight of 2 million Africans and cured 85 million people from river blindness * Specialised medical equipment
Incubators and ventilators for 65 hospitals; lending library for deaf children; neo-natal equipment for 23 hospitals; dialysis equipment for 20 hospitals; one renal failure unit for Great Ormand Street plus running costs for 3 years.