The current financial crisis may be more far-reaching than even the 1929 crash, a Bank of England policymaker has warned.
Professor David Blanchflower is a member of the Bank's Monetary Policy Committee (MPC), and has often been a lone voice in urging rate cuts.
Now he has said big interest rate cuts are needed to avoid a deep recession.
UK rates are at 4.5%, after the Bank cut them by half a percentage point earlier this month.
The cut was part of a co-ordinated move with both the Federal Reserve and European Central Bank (ECB).
On Wednesday the Fed cut its key rate further, to just 1%.
"My view remains that interest rates do need to come down significantly - and quickly," Prof Blanchflower told an academic audience in Canterbury.
"If rates are not cut aggressively we do face the prospect of a relatively deep and long-lasting recession."
'Synchronised downturn'
His comments follow those recently made by Bank of England governor Mervyn King and Prime Minister Gordon Brown that the UK is probably heading towards recession.
And Prof Blanchflower said international financial problems could turn out to have long-lasting repercussions.
"It is even possible that this event may turn out to be more significant than the 1929 crash which primarily involved bank failures in the United States," he said.
"The current difficulties in financial markets are more global in nature and more comparable to what happened in the First World War."
He also said a range of surveys of UK economic activity had shown a marked downturn since last summer.
"It is not sufficient to consider the data month by month until it emerges that the UK is in recession.
"I believe this trend has been apparent for some time. The synchronised downturn in so many business surveys should have led us to realise sooner that the UK economy was entering a recession."
