The U.K. Secretary of State for Exiting the European Union David Davis | Andy Rain/EPA UK paid consultants £1.9M for installing ‘Brexit computer system’ The project was deemed so sensitive that only British nationals could work on it.

LONDON — David Davis’ Brexit department paid consultancy firm McKinsey and U.S. infrastructure giant Bechtel £1.9 million to design and install a government computer system that helps civil servants overcome the “significant” challenge of delivering Brexit on time, according to a newly published contract.

According to the contract’s security stipulations, the project was considered so sensitive that only U.K. nationals employed by the two firms were allowed to work on it, and consultants were also banned from advising foreign governments or private companies on Brexit for two years after the project's completion.

It has previously been reported that McKinsey was contracted to help the Department for Exiting the EU coordinate hundreds of Brexit-related plans across government, but the precise nature of the contract has now been revealed in the transparency release.

The published contract — while heavily redacted — reveals that McKinsey sub-contracted part of the work to Bechtel, which alongside infrastructure projects, also specializes in project management.

Between them, the two firms provided DExEU with “Electronic Project Management (EPM) software,” as well as up to 20 staff seconded to DExEU for six months between April and October last year to manage the software and train civil servants in how to use it.

Non-British employees of the two firms were banned from working on the project because of security concerns.

Notably, in light of widespread criticism of the U.K. government’s indecision over its Brexit strategy, the contract stipulates that consulting staff assigned to the project “will need to be comfortable with considerable ambiguity” while working at the Brexit department.

Senior strategic consultants assigned to the project are told they will need “a close attention to detail, being comfortable moving between the big picture and the supporting detail, being adept at distilling a wide range of complex inputs to the simple ‘so what?’”

Non-British employees of the two firms were banned from working on the project because of security concerns, the contract states.

“Due to the highly sensitive nature of the work, all personnel must be UK nationals,” it says. Dual U.K. nationals would be considered on a case-by-case basis, the contract stipulates, and all staff assigned to DExEU were told they may be subject to interviews with government security advisers.

The McKinsey firm was also paid £680,000 by Her Majesty’s Revenue and Customs to develop the so called new customs partnership’ model.

Nationality restrictions on civil service staff and contractors are not unheard of in Whitehall and are usually only applied to work relating to security, defense, foreign affairs and diplomacy.

The contract states that the delivery of Brexit represents “a significant portfolio management challenge” to the government.

It is not the only Brexit contract McKinsey has won. They were also paid £680,000 by Her Majesty’s Revenue and Customs to develop the so-called new customs partnership model, one of the government’s two proposed alternatives to a customs union with the EU, which has been rejected in its current form by EU negotiators and also by May’s Brexit "war Cabinet." The firm also received an additional £54,000 from DExEU in March this year for “professional services,” according to government transparency releases.

A DExEU spokesperson said: "It is standard practice for a government department to draw on the advice of external specialists and we will continue to bring in expertise from outside as appropriate."

McKinsey and Bechtel declined to comment.