Real Madrid legend Iker Casillas once cost his family £1m after making huge mistake at the age of 7

Iker Casillas once cost his father £1 MILLION after making a hilarious blunder when he was just 7.

Casillas will go down as one of the greatest goalkeepers of his generation, having starred for club and country during his trophy-laden career.

He enjoyed a storied spell at Real Madrid, where he won five La Liga titles and three Champions Leagues.

The Spaniard also helped his national team to success, winning the World Cup in 2010 and the European Championships in 2008 and 2012.

Casillas rarely made a mistake between the sticks, but he made a huge blunder during his childhood which cost his family a whopping £1 million.

One day, Casillas' father selected 14 teams on an accumulator and passed his lucky slip onto the future captain of Los Blancos and Spain, instructing him to place his bet for him.

What could possibly go wrong...

Iker Casillas in action for Real Madrid. Image: Getty

Well, a young Casillas never made it to the bookies and, as you can probably guess, all 14 of his father's selections came in.

The forgotten slip would have brought £1 million to the Casillas household. So, it's probably a good job he went onto become one of the greatest and most decorated goalkeepers in history.

Luckily for Casillas senior, his son would go onto become a mega star in the sport and earn millions throughout his playing career.

Having said that, the lesson to be learned here is if you have a budding accumulator don't leave it in the hands of a child.