Suella Braverman maintains “strong relationships” with the security services, Downing Street insisted after Tory MPs expressed concern over her reappointment as Home Secretary.

Rishi Sunak was under growing pressure over his decision to resurrect her in the role just six days after she was forced to resign by Liz Truss over a security breach.

Labour accused the Government of a “farcical lack of scrutiny” as Cabinet Secretary Simon Case resisted demands to open an inquiry into her rehiring.

Conservative Party chairman Nadhim Zahawi said she deserves a “second chance”, after her first stint made her the shortest-serving home secretary in history.

But other Tories raised doubts, with Caroline Nokes backing opposition calls for an inquiry and Mr Zahawi’s predecessor Sir Jake Berry describing the breach as “really serious”.

Mark Pritchard, who used to sit on Parliament’s Intelligence and Security Committee, said a “breakdown” in trust between MI5 and Ms Braverman must be “sorted ASAP”.

His comment came after suggestions Ms Braverman had earlier been investigated by Government officials after the leaking of a story involving the security services.

The Prime Minister’s official spokesman was moved to insist MI5 is confident in Ms Braverman.

“The Home Secretary continues to have strong relationships with all the operational bodies that report into the Home Office and are focused very much on keeping the country safe,” he said.

Mr Sunak brought Ms Braverman back into the Cabinet despite her resignation after she was caught sending a Tory backbencher a sensitive document from a personal email account, twice breaching the ministerial code.

Allies of the minister dubbed “Leaky Sue” insisted a suggestion that MI5 will give her lessons on what information she can and cannot share to prevent another breach was “nonsense”.

The Mail reported that she had been investigated by a unit within the Cabinet Office over a leak about the Government’s plan to seek an injunction against the BBC.

The newspaper said no “conclusive evidence” was found about the identity of the leaker of a story about plans to bar the identification of a spy accused of terrorising his ex-partner.

But it said MI5 played a role in the inquiry after the leak at the time Ms Braverman was attorney general sparked “concern” in the Security Service.

Mr Pritchard tweeted: “MI5 need to have confidence in the Home Secretary – whoever that might be.

“It’s a vital relationship of trust, key to the UK’s security and democratic oversight of MI5. Any breakdown in that relationship is bad for the Security Service and the government. It needs to be sorted ASAP.”

Ms Nokes, who chairs the Commons Women and Equalities Committee, said there are “big questions hanging over this whole issue”.

“And to be frank I would like to see them cleared up so that the Home Secretary can get on with her job,” she told the BBC.

“If that means a full inquiry then I think that’s the right thing to do.”

But Mr Case, the top civil servant who was reportedly “livid” about her swift return and “very concerned” about the breach, was understood not to be launching an investigation.

Deputy Labour leader Angela Rayner said: “This farcical lack of scrutiny, transparency and accountability does diddly squat to deliver on the new Prime Minister’s promise to restore standards in public life after years of Tory sleaze and scandal.”

Meanwhile, Labour was calling for clarity after Mr Sunak’s insistence in the Commons that Ms Braverman “raised the matter” was apparently contradicted by Sir Jake.

“As I understand it, the evidence was put to her and she accepted the evidence, rather than the other way round,” he told TalkTV.

Downing Street insisted Mr Sunak’s account was accurate.

“He said she had raised it, I’m not going to get into conversations and timelines around this. As we have said before, the Home Secretary made an error of judgment and took accountability for her actions,” his spokesman added.

Mr Zahawi defended her reappointment, arguing that she admitted the “mistake” and resigned “immediately”, a characterisation disputed by officials.

“She fell on her sword, she didn’t try to ride it out and try to hang on to her job,” he told BBC Radio 4’s Today programme.

“This Prime Minister looked at the details of this case and he believes in second chances and he’s giving Suella Braverman a second chance. I believe in redemption, as I’m sure many of your listeners would do as well.”

Meanwhile, Downing Street sought to reassure pensioners as Mr Sunak refuses to commit to the triple-lock ahead of the autumn budget on November 17.

Failing to increase payments in line with inflation at more than 10% in April would deliver real-terms cuts to millions of pensioners.

The Prime Minister’s official spokesman said: “Decisions will be guided by the values of the Government and will be done with compassion.

“We do recognise that uncertainty is difficult for pensioners and other groups of people. That’s why the Prime Minister and the Chancellor believe it is right to take the time to work carefully and diligently to come up with proposals that will provide that certainty in the long term.

“Given the very challenging economic circumstances the country and indeed the world faces, it is right that we take that time so that we put in place measures that can last.”