The Archbishop of Westminster, the Most Rev Vincent Nichols, said: "It is now widely acknowledged that underlying the banking crisis was the gradual erosion of the duty of service to society.
"A market mentality which focused relentlessly on the search for ever greater and quicker profits, exploiting to the full the regulatory opportunities available, allowed many to lend and deal recklessly."
Writing in the Sunday Telegraph, the Archbishop said ethical leadership was needed in the financial sector and in deciding the shape of the forthcoming Budget.
The Archbishop said: "The outcome needs to be fair and seen to be fair. There also needs to be clarity of process so that we understand and are as involved as possible in a process that will affect us all."
He added that support for the Government would depend to the extent to which it was seen be acting prudently and that resisting cuts to the overseas aid budget would send a positive message.