Britain's Queen Elizabeth II put central bankers on the spot when she quizzed them about the errors that led to the 2008 financial crisis in a rare public grilling during a visit to the Bank of England on Thursday.

She asked whether complacency was a cause and if the financial watchdog lacked teeth, touching on a debate that has raged since the near collapse of the banking system and triggering widespread attention in the British media.

Britain's Queen Elizabeth II walks through a gold vault at the Bank of England in London on Thursday. [Photo/Agencies]

The 86-year-old monarch avoids entering political debate, but four years ago pointedly asked academics why nobody had foreseen the crisis, which forced Britain to rescue leading banks, stoked a record budget deficit and sent the economy into recession.

Bank of England employees attempted to answer her inquiry during her visit, giving a technical explanation that prompted the queen to explore the subject further.

"I suppose in money terms it is very difficult foreseeing (things). But people had got a bit ... lax?" she said, before agreeing with an official that the real problem could have been "complacency".

She asked whether the bank regulator at the time lacked the powers it needed, reflecting plans to abolish the Financial Services Authority and divide its responsibilities between the Bank of England and a new watchdog.

"It was really quite new, wasn't it? But it didn't have any teeth or something?" she asked in comments captured in television footage of the visit.

The central bank team giving the Queen an account of the crisis were introduced to the monarch by an official as "some of the staff who hopefully will spot the next one coming".

Her 91-year-old husband, Prince Philip, also on the visit and fond of making off-hand quips, prompted nervous laughter when he responded, "There isn't another one coming, is there?"