A Dutch security expert has warned that the UK is highly likely to use cyberhacking to gain an advantage in the Brexit negotiations.

Ronald Prins, founder of digital security firm Fox IT, told NRC that the British intelligence agency GCHQ had a track record of spying on its partners during cross-border discussions. In documents leaked by the former CIA employee Edward Snowden, it described its interventions in the ill-fated Copenhagen climate change summit in 2009 as ‘a success’.

‘The chances of the British hacking the Brexit negotiations is high on my list,’ said Prins. ‘I am certain that they will infiltrate everywhere and we won’t be able to resist them.’

Prins’s company uncovered a sophisticated hacking operation by GCHQ targeted at the Belgian telecoms business Belgacom. The agency used an advanced virus to access the systems of Belgacom, which handles mobile phone and data traffic for 400 companies around the world including Dutch phone providers KPN and T-Mobile.

The modular nature of the virus and its ability to adapt itself to different systems made it highly difficult to detect and remove, said Prins, who called it ‘one of the best that our hackers have ever seen’.

The AIVD and MIVD intelligence agencies declined to comment when approached by NRC.