IT might not have carried out an impact assessment on Brexit, but the UK Government believes it has a secret weapon in the battle to withdraw from the EU – a new spook.

MI5 is trying to recruit a new official to stop “sensitive information” from leaking during the Brexit negotiations and damaging the UK Government. The security service, which is the country’s domestic counter-intelligence agency, advertised for the “high impact” role last month after a spate of unauthorised disclosures about the talks.

Liberal Democrat MP Christine Jardine said: "This is utterly embarrassing. Brexit is clearly such a bad idea they've had to hire a spook to try to stop people finding out the terrible truth. Given how clueless the Cabinet seem, it's doubtful if there is any real information under wraps."

Prime Minister Theresa May endured a bruising few days last week amid continuing problems over the process of the UK leaving the European Union.

One of the red lines issues that had to be resolved – whether there will be a hard border in Ireland after Brexit – appeared to be in danger after the Democratic Unionist Party cried foul.

Part of the difficulty can be traced to a leak to the Irish media about the negotiations, which the DUP interpreted as coming from the Irish Government.

The leak jeopardised the talks, but all sides reached an uneasy truce on Friday and the process will continue at a meeting of EU member states this week.

It was also not the first time that a leak embarrassed the UK Government during its troubled bid to strike an acceptable deal with EU partners.

In October, a German media outlet revealed what it reported as leaked details of a private dinner between May and senior EU figures such as Commission President Jean-Claude Juncker.

It was claimed that May, who was described as “anxious”, “tormented” and “despondent”, had pleaded for support around the table.

Similarly, details of a dinner between May and Juncker earlier in the year at Downing Street also made their way into the press. Juncker was reportedly said Brexit “cannot be a success".

The Sunday Herald can reveal that MI5, which is led by Andrew Parker, recently advertised for a “head of protective security advice” to the Government.

The job description raised a range over a number of subjects, including how the Government can protect itself from terrorist and espionage threats, as well as how MI5 can help Ministers avoid being compromised by “hostile state actors” while overseas.

However, the advert also asks: “How can sensitive information relating to BREXIT negotiations and trade deals be secured?”

The job specification includes managing a team of specialist advisers, liaising with the Cabinet Office and co-ordinating a programme of security briefings at a ministerial level.

The closing date for the post was November 27 and the job is based in London.

Labour MP Ian Murray said: “It’s hardly surprising the government needs the advice of the security services to keep Brexit details secret given the debacle of this week where the Brexit Secretary denied having the very sectoral analyses he said he had just a few months ago.

"It appears that ‘taking back control’ means taking power back in secret for Ministers who are holding the public and parliament in contempt with their embarrassing Brexit shambles.”

The Home Office, which handles press enquiries on behalf of MI5, said it did not comment on security service job adverts.