Northern Rock Plc, which suffered the first run by British bank depositors in more than a century, may remain nationalized for years to come, according to the chairman appointed by Prime Minister Brown’s government.

“We are clearly talking about a period of some years,” the Treasury-appointed leader of the bank, Ron Sandler, said at a press conference yesterday in Newcastle, England.

Mr. Brown said he wanted a “temporary period” of ownership for the bank that tapped British authorities for loans and guarantees of $107 billion since September, when its credit lines in financial markets dried up. Bringing the bank under the wing of the state will leave government ministers responsible for assets of 113 billion pounds and 6,500 employees, damaging Mr. Brown’s reputation for smooth management of the economy. The Conservative opposition said it would vote against the matter in Parliament. “Let’s be in no doubt about what a disaster this day is,” the leader of opposition Conservative Party, David Cameron, said. “The nationalization of Northern Rock is a disaster for the British taxpayer, a disaster for this Government and a disaster for our country.”