Mr Brown said people could not be left to their own devices
The government must be a "rock of stability" for British people during the credit crisis, Prime Minister Gordon Brown has said.
The Treasury is to inject up to £37bn of new capital into Royal Bank of Scotland, Lloyds TSB and HBOS.
Mr Brown told a press conference people could not be left to be "buffeted about" and banking was a "lifeline".
It was not "standard public ownership" and the banks would return to private investors "at the right time", he said.
Mr Brown later told a City audience that he wanted world leaders to gather for a new Bretton Woods - the conference held in 1944 which helped draw up the post-war financial order.
He said there had to be "a new financial architecture for the years ahead", with global supervision to match a world where money flows across borders and firms operate multi-nationally.
Mr Brown, speaking at Reuters in Canary Wharf, said he had sought to bring in such changes since 1998, but there had always been something more pressing for other countries to worry about.
He added: "Sometimes it does take a crisis for people to agree that what is obvious and should have been done years ago can no longer be postponed."
The prime minister said the action the government was taking over banks was "unprecedented but essential".
He said: "In extraordinary times, with financial markets ceasing to work, the government cannot just leave people on their own to be buffeted about.
"For savers, for small businesses, and for homeowners, we must in an uncertain and unstable world be the rock of stability on which the British people can depend."
Mr Brown added: "To let the chits fall where they may would be the height of irresponsibility.
"It would be a failure of leadership at precisely the moment vigorous action is needed to protect people who need that help the most.
"And if we pull together as a country, we can come through these times stronger and not weaker.'
Board members of the affected banks would not receive bonuses in the immediate future and thee would be no dividends paid until government preference shares were repaid, the prime minister said.
He added: "Our action is driven by our values. For this government, and I believe the whole country, the guiding idea is fair reward for hard work, effort and enterprise, not incentives for irresponsibility or excessive risk-taking for which the rest of us have paid."
Mr Brown, who agreed that the stakes were high, said he would rather not be taking stakes in banks - but said he was doing what was essential to build trust in the financial system.
For the Conservatives, shadow chancellor George Osborne said the package was "no triumph" for the government and accused the prime minister of "presiding over the biggest economic disaster of our lifetime".
Liberal Democrat Treasury spokesman Vince Cable said the government needed to be "tough" in its arrangement with the banks on behalf of taxpayers whose cash will be used to help keep them afloat.
On Sunday Mr Brown met fellow European leaders to discuss the crisis, saying afterwards that he believed confidence in the banking system would be restored by global action "in the next few days".