It is understood the attack is not connected to the devastating cyber attack on the Solar Winds Orion software, which US officials pin on Russian hackers.
The Foreign Office has not commented on any suspects of its investigation, but tonight confirmed the breach, which was first reported by The Sun.
A Government spokesperson said: ‘We take data security very seriously. There is no evidence at this stage that data has been taken following a cyber incident at Wilton Park.’
Officials stressed that Wilton Park’s computer system is less secure than the Foreign Office’s IT, which holds classified information.