The day zero was banned from British roulette – how times have changed

Feeling lucky? Stuart-Buchanan, CC BY-SA

On December 30, 1967, senior detectives from Scotland Yard sent owners of gambling clubs into a proverbial spin. Anyone operating a roulette wheel that contained the number zero would be prosecuted, they warned. From now on the whirl of numbers would all be reds and blacks – starting with the number one.

This warning 50 years ago followed a judgment in the House of Lords, the country’s highest court of appeal at the time, that the green zero was illegal under gaming law. According to these so-called “law lords”, this was because the chances must be equally favourable to all players in the game.

The Lords’ problem with the zero was that players betting on the ball landing on an individual number were being offered odds of 35/1 – put £1 on number 7 and if it came up you got £35 back plus your stake. But standard British roulette wheels have 37 numbers including zero, so the odds should have been 36/1.

This discrepancy gave the house an edge of 2.7% – the proportion of times the ball would randomly fall into the zero slot. (Note that in the US and South America roulette wheels normally have both a zero and double zero, giving them a house edge of just over 5%).

The British edge on roulette wheels was a small one, such that someone staking £10 on a spin would expect statistically to lose an average of 27 pence. But it’s a vital one. Without an edge on a game the operator would expect only to break even, and that’s before accounting for running costs. The Lords’ decision also looked like the back door to banning every other game with a house edge, such as blackjack and baccarat.

Casinos royale

It had been illegal in the UK to organise and manage the playing of games of chance since the Gaming Act of 1845. The Betting and Gaming Act 1960 was the most substantive change to gambling regulation since then. As well as permitting the likes of betting shops and pub fruit machines, it opened the door to gambling halls – though only in a very restricted way.

Designed to permit small-stakes play on bridge in members’ clubs, the act legalised gaming clubs so long as they took their money from membership fees and from charges to cover the cost of the gaming facilities. Casinos soon proliferated, however, and by the mid-1960s around a thousand had sprung up.

Many introduced French-style roulette, with wheels that included a single zero, since the law had arguably not been clear as to whether the house could have an edge. The one variation thought necessary by some to comply with the legislation was that when the ball landed on zero the house and player split the stake, instead of it being kept by the house.