Tomorrow Channel 4 is courageously broadcasting an hour’s viewing devoted to The Knowledge, or more specifically, one of the schools and its pupils. “If it’s not taking over your life, you’re not doing it properly.” So says one of the examiners for The Knowledge, the infamous test of London’s 25,000 streets; the tens of thousands of places upon those streets, added to the traffic restrictions and the little matter of holding down one’s existing job.

[O]nce qualified the novice London Licensed Black Cabbie becomes a human satnav, in fact, they have more expertise in finding their way across their city than any other taxi driver in the world.

In the programme we see several candidates sweat through the one-on-one examinations they have to sit.

These ought to be tedious to watch:

Leave on left: Green Lanes
Right: Highbury New Park
Left: Highbury Grove
Right: St. Paul’s Road
Comply: Highbury Corner
Leave by: Upper Street
Right: Barnsbury Street
Left: Milner Square
Forward: Milner Place
Forward: Gibson Square

They are just a recital but have the tension of a high-stakes quiz show or one of those evil spelling tests on Child Genius.

Often compared to studying for a degree (although The Knowledge does take longer) the candidates have sunk years of their lives and thousands of hours of study into mastering the map of London.

When they stumble, you feel their pain; when they cross the final hurdle, it’s emotional for all concerned.

The 6-mile radius that has to be learned

I described Channel 4’s decision to screen the documentary as ‘courageous’ for this behind-the-scenes looks at one of the world’s toughest exams which could be its swan song.

Because of recent decisions taken by Transport for London the take-home pay – after covering their overheads – of London’s cabbies is about the same hourly rate of that of a London bus driver. As a result over time recruitment of those willing to undertake The Knowledge will just dry up.

Since Cromwell licensed the London cab trade in 1654 – and in so doing making it the oldest regulated public transport system in the world – and the advent of The Knowledge after the Great Exhibition of 1851, many have tried to destroy London’s cab trade and been proved singularly unsuccessful.

The watermen plying the Thames were the first to try their luck when the early bridges were built, claiming that cabs couldn’t ‘go South of the River’; in 1961 exploiting a loophole in the 1869 Carriage Act, Michael Gotla spent £560,000 buying 800 red Renault Dauphines expecting that the drivers could ‘ply for hire’. Unfortunately for Gotla within a year, the courts begged to disagree with his interpretation of the law.

His rather costly enterprise did have one consequence, and that was encouraging anyone with a rusty Datsun to attach an aerial to its roof, sign on at a dodgy ‘mini-cab’ office, and chance his luck on London’s streets at the weekend. It would be many years before their act was cleaned up.

Others have called for a truncated Knowledge, fast-tracking students to increase the numbers on the road, or for allowing those final year students to be let loose on the capital’s streets in the hope they know where they were going. All of these cunning plans have come to zilch.

But, I’m afraid Transport for London has won. With students unwilling to put their lives on hold as they pursue The Knowledge this proud service, the envy of the world, will wither on the vine.

The Knowledge: The World’s Toughest Taxi Test – Channel 4 21.00 Wednesday 12th April.

If you want a better insight into The Knowledge I can highly recommend Black Cab London here Robert takes you through all the hurdles necessary to pass. I have also used his map to illustrate the 6-mile radius.