A minister has come under fire for suggesting there could be “some little man in China” eavesdropping on his own private conversations as he fielded questions over security breaches concerning senior Government figures.

Former chief whip Mark Spencer stressed that ministers must be “super-careful” about where they access information, as he said Liz Truss was “clearly” hacked when she was foreign secretary, following reports that her phone was targeted by Russian spies.

On the suggestion that it was Ms Truss’s personal phone which was subject to the breach, he said it is possible his own conversations with his wife are being listened to by “some little man in China” – sparking a backlash from opposition MPs.

Shadow ministers Afzal Khan and Sarah Owen accused Mr Spencer of using “outrageous and reckless language”, showing his “ignorance, on many levels”.

Labour whip Chris Elmore hit out at “the state of this”, while his parliamentary colleague, Chris Bryant, appeared incredulous, tweeting: “Little man”? Honestly?”

It comes as the Government has faced accusations of “ill discipline” and not taking national security “seriously enough”, with criticism of Home Secretary Suella Braverman’s return to the role after being forced out for sharing a sensitive document with a Tory backbencher from a personal email.

On Sunday, Cabinet minister Michael Gove declined to deny an incendiary report that Ms Truss’s personal phone was accessed by Kremlin agents, as he insisted the Government has “very robust protocols” in place.

But Mr Spencer, a minister in the Department for Environment, Food and Rural Affairs, said during a round of interviews on Monday that Ms Truss was “clearly” hacked.

“The former prime minister clearly was hacked,” he told Sky News.

“So, that is the first thing you do, say ‘Oh my goodness, I’ve been hacked, help’, and the security services will help you with that challenge.

“Now, of course, you don’t always know, which is why you’ve got to be super-careful.”

The Mail on Sunday reported that the agents who hacked Ms Truss’s phone were thought to have gained access to sensitive exchanges with foreign officials on Ukraine, as well as private conversations with Kwasi Kwarteng.

Questioned on the potential breach, Mr Spencer said: “We all talk on personal phones, don’t we? I ring my wife, maybe there’s some little man in China listening to the conversations between me and my wife.

“But, you know, you’ve just got to be careful about what information you use on which phone and you get a lot of help and support from the security services on that.”

He said ministers get “quite a lot of briefing” on “what to do and what not to do”.

Asked if he uses his Government phone for personal business, he said: “I do not, no.”

He added: “You do get quite a lot of briefing from the security services on what to do and what not to do. So, you know, it’s quite important to get that right.

“I don’t want to comment too much on it because, of course, what I don’t want to do is tell the world exactly what that briefing says. But you do get a lot of support when you become a Government minister on what is appropriate and inappropriate as a Government minister.”