BREXIT Secretary David Davis has been warned he is being spied on by every other government in the EU, The Sun can reveal.

The Cabinet minister was told as soon as he took up the crucial post that he should expect all other 27 member states to be trying to intercept his phone calls and overhear his private conversations.

5 Brexit secretary David Davis has been warned EU governments will be trying to hack his phone Credit: PA:Press Association

The warning was issued to him by Whitehall mandarin Oliver Robbins, the top civil servant in Mr Davis’s ministry, the Department for Exiting the European Union.

Mr Davis has told a friend that Mr Robbins - a former Deputy National Security Adviser who oversaw intelligence - told him he was now “a painted man”.

Ex-SAS reservist Mr Davis is one of just a handful of people who will know Theresa May’s secret negotiating hand once it is drawn up.

5 The warning came from Oliver Robbins, a former Deputy National Security Adviser who is now in the Department for Exiting the European Union

Discovering the PM’s bottom lines in the high stakes game of brinkmanship will give any other EU state a major advantage to call her bluff.

As allies, European Union states are not supposed to conduct espionage operations against each other, but it is known they do.

Last year, Cheltenham-based eavesdropping agency GCHQ was accused of bugging a laptop used by an official in German Chancellor Angela Merkel’s own office.

5 Last year a laptop belonging to an official in Angela Merkel's office was allegedly bugged Credit: Rex Features

Then, Berlin itself was accused of secretly monitoring emails and telephone calls made in the French Presisdent’s Paris home, the Élysée Palace, as well as EU institutions in Brussels.

The revelation comes as Theresa May tomorrow offers the governments of Scotland, Northern Ireland and Wales regular talks with Brexit boss Mr Davis to help define the UK’s exit deal.

The summits are a bid to calm angry Scots and Ulster residents’ fears about leaving the EU, after both voted by a majority for Remain in the landmark June 23 referendum.

5 Theresa May is set to call Scotland's First Minister Nicola Sturgeon and the heads of states for Wales and Norther Ireland to a meeting to discuss Brexit Credit: PA:Press Association

The PM will issue the offer at the first meeting in two years in No10 today of the Joint Ministerial Committee of her, Scotland chief Nicola Sturgeon, Wales’s Carwyn Jones, and Belfast’s Arlene Foster and Martin McGuinness.

Mrs May said last night: “The great union between us has been the cornerstone of our prosperity in the past - and it is absolutely vital to our success in the future.

“The country is facing a negotiation of tremendous importance and it is imperative that the devolved administrations play their part in making it work.”

5 The summit is part of the PM's plans to calm the angry nations and keep them from demanding independence from the UK Credit: Alamy

During the summit, the PM will also slap down Cabinet ministers for briefing out plans about Brexit to insist that “contrary to some speculation, no final decisions have been taken”, No10 said.

Mrs May will also argue that Brexit will not be “a binary choice” between free trade and immigration control as the UK can win both.

A major cut in Corporation Tax emerged as a new weapon in the talks yesterday.

Cutting the levy in half from its current 20% rate to 10% would be a “nuclear option” to make up for crippling trade tariffs if the EU enforces a hard Brexit on us.

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The move would infuriate the 27 other members by heavily undercutting their tax regimes and giving businesses a big incentive to stay.

Scotland First Minister Nicola Sturgeon last night called on Mrs May to consider delivering "flexible Brexit".

Under her idea, parts of the UK that want to stay in the EU's single market such as Scotland or London could, while areas that voted firmly to leave would break away.

A spokesman for Mr Davis refused to comment.