"If you want to compete at the top level you must be able to spend a lot of money, not only on your first team, but on the young players and reserves," he said.
"Sometimes we go too slowly as a club to make signings we need, and when we do there is not a lot of money. Arsenal spent £4m on Abou Diaby, £4m on Denilson, £8m on Theo Walcott.
"They have been working for 10 years to build a strong squad and we have been working for two."