Manchester United boss Jose Mourinho says this summer's explosion in transfer fees hasn't surprised him.

Mourinho can understand Manchester City making Kyle Walker the most expensive fullback signing in history.

"The transfer fees don't surprise me, really," said Mourinho. “I keep saying there is big economic power at every club. It allows clubs to say 'no' to say 'pay what I want or you don't get it'.

“I can imagine City would like to have paid £25m for Kyle, but they were told 'this is the price'.

“The option is to pay or not. I'm used to clubs paying big amounts for big players. Now everybody pays big amounts for good players.

“There is a difference between big players and good players."