FILE PHOTO: Workers are seen crossing the Millennium Bridge, with St Paul's Cathedral seen behind, during the morning rush hour in London, Britain, September 25, 2018. REUTERS/Toby Melville/File Photo

LONDON (Reuters) - Britain’s private sector has had its worst three months in nearly seven years as the Brexit impasse and poor weather hit economic growth, the Confederation of British Industry said on Sunday.

After a surge earlier this year, caused by companies stockpiling ahead of the original March 29 Brexit deadline, private sector activity in the three months to June contracted at the quickest pace since September 2012.

The balance of firms reporting growth sank to -13%, according to the CBI’s monthly Growth Indicator.

Rain Newton-Smith, the CBI’s chief economist, blamed the weakness on the after-effects of the stockpiling rush, Brexit-related shutdowns in Britain’s car industry and bad weather.

“But underlying activity and confidence is clearly subdued,” she said. “The UK economy is being stifled by uncertainty about the UK’s relationship with the EU. The need for the new prime minister to secure a deal with the EU is urgent.”

Britain’s Conservative Party is due to announce its new leader, who will become the next prime minister, on July 23. Both contenders - former foreign minister Boris Johnson and the current incumbent Jeremy Hunt - have said they are prepared to lead Britain out of the EU without a deal if necessary.

The Bank of England has said it expects zero growth in the economy in the second quarter, reflecting the unwinding of the stockpiling boost in the first three months of the year, uncertainty about the Brexit outcome and slower global growth.