A British man and a woman have been arrested in London after Washington DC's CCTV cameras were hacked just days before Donald Trump's inauguration.

Police stormed a house in south London after the cyber attack was launched on the network - crippling 123 out of 187 cameras.

The day before President Trump was sworn into the Oval Office on January 20, the National Crime Agency raided a property in Streatham and arrested a British man and a Swedish woman, both 50 years old.

Natal Road in Streatham where the raid and arrest took place

Washington officials said the hack last week saw ransomware left on the camera system between January 12 and January 15 in a bid to extort cash from the authorities.

City officials were left unable to record, forcing major citywide reinstallation efforts, according to the police and the city's technology office.

And US authorities believe the cyber attack may have been a test run with another computer assault potentially planned for the day of the ceremony.

A spokeswoman for the NCA would not confirm what was found at the address, but added: 'We can confirm that officers executed a search warrant at an address in Natal Road, SW16 on the evening of 19 January.

Donald Trump gives a thumbs up to attendees of his inauguration on January 20. The hack was made between January 12 and January 15

'Enquiries are ongoing and we are unable to provide further information at this time.'

No ransom was paid to the hackers and the issue was resolved internally by reinstalling software and restarting each infected system individually.

The arrested pair have been bailed until April 2017.