Joseph Blatter, ex-secretary general of UEFA and ex-president of FIFA, has admitted that "hot and cold balls" were used to fix European draws at UEFA during the stewardship of Michel Platini in an interview with Argentine paper 'La Nacion'.

Interview with Blatter over rigged draws

Here's the excerpt where Blatter talks about how the draws were rigged:

Interviewer: The draw for Brazil 2014 was extremely beneficial for Argentina. The theory circling was that if Grondona and Blatter were at war, Argentina would pay for it with a bad draw, and that if the two were getting on, the draw would be more favourable.

Blatter: There was only one person with that power in Europe. Artemio Franchi (The UEFA ex-president) used to do it for the club tournaments. I didn't do it for the World Cup 78, I just made everything happen by magic. Again, that's a joke. The draw was clean down to the last detail. I never touched the balls, something that others did. Of course it's possible that the balls can be hot or cold and signalled in that way.

Blatter says UEFA draws rigged

So the theory of hot and cold balls is a reality

Blatter: Of course it's possible, technically. It doesn't happen in FIFA, but I've witnessed draws at European level where it's happened, but never in FIFA. Of course it can be done, but it never happened under my watch, never.

Balls in the freezer

How does it work exactly?

Blatter: Balls are put in the freezer before the draw, at the slightest touch you can tell if the balls are hot or cold. By touching them you know exactly what you have.