Britain's economy grew faster than expected in the third quarter, revised official data showed Friday, indicating no impact yet from the nation's looming exit from the European Union.

Gross domestic product expanded by 0.6 percent in the three months to the end of September, up from the previous estimate of 0.5 percent, the Office for National Statistics (ONS) said in a statement.

Activity was greater than expected due to upward revisions on the output of the business services and finance industries, it added.

"Robust consumer demand continued to help the UK economy grow steadily in the third quarter of 2016," noted Darren Morgan, head of GDP at the ONS.

"Growth was slightly stronger than first thought, though, due to greater output in the financial sector.

"New figures on services also suggest that growth in that predominant sector of the economy continued into October, helped in large part by another strong showing from the retailers."

The ONS meanwhile revised down its growth estimates for the first and second quarters by 0.1 percentage points, to 0.3 percent and 0.6 percent respectively.

"The fundamentals of the UK economy are strong, but there remain challenges ahead," a Treasury spokesman said.

Economists point to an economy intact since the June 23 referendum in favour of Britain leaving the EU -- but some also warn of looming trouble.

"The latest set of UK national accounts leave the economy looking even stronger after the referendum than previously estimated," said economist Ruth Gregory at research consultancy Capital Economics.