Britain's economy continued to expand in the three months to October, but the euro zone debt crisis poses a serious threat to the recovery, a respected economic think tank said on Tuesday.

Gross domestic product grew by 0.5 percent in the period, maintaining the same pace of growth as in the three months to September, the National Institute of Economic and Social Research said in its monthly estimate.

NIESR's data comes after official figures last week showed the economy grew by 0.5 percent in the July-September period, but the think-tank warned there were risks ahead.

It is welcome news that the UK economy has continued to expand. But the UK faces significant headwinds from the euro area's sovereign debt crisis, NIESR said in a statement.

Official data on Tuesday showed British industrial output flatlined in September, despite a modest rise in manufacturing output. Last month's manufacturing purchasing managers survey showed domestic and export orders shrank in October, fuelling worries the economy could suffer another downturn.

NIESR said it did not expect the level of economic output to pass its 2008 pre-recession peak until 2013.

(Reporting by Fiona Shaikh; editing by Anna Willard)