Manager Mark Hughes has already spent £12m for Aston Villa captain Gareth Barry since the campaign ended.

And Al Mubarak revealed more signings will be made as City aim to challenge for honours in the Barclays Premier League next season.

Al Mubarak said: "We will shrink our squad and add four to six players.

"Key for us is that we trust Mark Hughes and any acquisition is based on his view.

"But I'm frustrated that people assume we are going to throw crazy money at deals, that we won't understand true values and we can't negotiate or get value for a player.

"We've had numbers thrown at us that are a joke. There are situations where a £10m player will be offered to us for a 'City price' of £20m. We just leave because at that point there's no point arguing - if people are throwing crazy numbers at us, fine, deals won't be done.

"Look at (City owner) Sheikh Mansour. He's a very shrewd businessman who has conducted himself in a professional way. I will defend the value of every deal we have done.

"Look at our Robinho deal. If he went in this transfer window for the same price it would be a steal.

"Our deals to date presented fair value to the clubs we brought them from, fair value to us and are typical of the type of deals we are looking to make."