However, individual £1 bonds are given unique bond numbers and entered into the draw, meaning that the more money bond holders put in, the higher the chances of one of their bonds being chosen. 

Martin Lewis calculated the chances of winning the different Premium Bonds prizes based on a £1 bond. 

He found that the chances of winning the £1million jackpot was one in 57,837,067,198.

As the prize amount lowers, the chances of winning increases as more low value prizes are given each month than high value ones, but even the £25 prize saw a chance of one in 34,500.