“There certainly has been a hack,” Bryant told Times Radio.

“I’m not able to say whether it is directly related to Chinese operatives, or indeed, the Chinese state,” he added.

The Sun named Storm 1849 as the Chinese cyber gang responsible for the breach, which it said was understood to possibly include tens of thousands of Visa details.

Bryant said that the reporting around the incident was “speculation” and that the government was continuing to investigate, but at this stage, it was “fairly confident” that there was a low risk any individual would be affected.

“We managed to close the hole, as it were, very quickly,” Bryant told Sky News, describing the breach. “It was a technical issue in one of our sites.”

The Sun newspaper said the group, Storm 1849, was a China-linked gang which was part of a state-aligned hacking apparatus, and which has been accused of targeting politicians and groups critical of the Chinese government.

British Prime Minister Keir Starmer said earlier in December that China posed “national security threats” to Britain, but defended his government’s decision to step up engagement with the country.

He is due to visit Beijing in late January, according to sources.

The incident at the Foreign Office follows two major cyber attacks on big British companies this year.

Hacks forced the country’s largest car maker, Jaguar Land Rover, to shut down production for five weeks, while retailer Marks & Spencer suspended online orders for six weeks.

Asked for details of the incident, the Foreign Office said that it had been working to investigate a cyber incident.

“We take the security of our systems and data extremely seriously,” a government spokesperson said.