The Liberal Democrats have pledged to create a "completely different ecology of banking" by breaking up the banks and making sure they lent to their customers.
Party leader Nick Clegg said power had been "too concentrated in a few super-banks" and it was time for a "totally different financial system".
At a press briefing in central London he set out plans to split up the banks, to separate low risk deposit-taking banking from high risk investment banking, and set a new 10% levy on bank profits.
There would be new, "non-negotiable" lending targets for both Lloyds and RBS for 2010-11, to ensure that money available to British businesses increased over the next 12 months.
And the Lib Dems would support new and growing businesses through the creation of Local Enterprise Funds and Regional Stock Exchanges.
Mr Clegg said: "At the heart of our plans for economic change is a simple insight: we need to devolve and disperse economic power, particularly in the banking sector.
"Most people, except perhaps Gordon Brown, now recognise that too much centralisation in politics has led to wasteful bureaucratic public services, a command-and-control state that leeches power away from people. I believe the same analysis can be made of our economy. Power has been too concentrated in a few super-banks.
"The building societies and regional banks that used to be the bedrock of family and small businesses' access to credit have been swallowed up. And accessing equity investment, so you don't have to rely on loans to grow your business, can be almost impossible unless you're already big enough to cope with the burdens of listing on a stock exchange in London."
Mr Clegg said he recognised that breaking up the banks was complex and would take time. Until the banks were split, the taxpayer had to continue underwriting them - so the Lib Dems therefore proposed a new levy on bank profits at a rate of 10%.
This levy would be on top of corporation tax and payable on all profits made within the tax year, without the deduction of previous years' losses.