It’s a known as the Martingale method and is very well known.

In theory yes it would always work if you had unlimited money but in reality it’s quite easy to run out of money quickly, with £10 a time you only a good streak of losses before you’re getting into big numbers and most tables will have a table limit on red and black.

What you’re actually doing is offsetting your odds by increasing your stake. So you’ll win £10 again and again and again, then suddenly you’ll lose a big sum which will wipe out all your winnings.