Newcastle United owner Mike Ashley admits they will start including bigger buyout clauses in future player contracts.

Ashley admits they were caught out by Leicester over Ayoze Perez.

The attacking midfielder, one of Newcastle's stand-out players under Rafa Benitez last season, was bought for £30million this summer, after Leicester triggered his release clause.

"We didn't want to sell Perez, but had no option once Leicester reached that figure," he told the Daily Mail.

"These clauses are the highest you think the player will accept, so he can't batter your door down and demand to be sold for £10m. I don't care what people say, it's very difficult to keep a player when they want to go. The age of slavery is dead. But we've learned our lesson on release clauses from here."