Following Labour’s Commons victory, the UK government will have to decide how much ‘excruciating detail’ it is prepared to reveal

Black marker in hand, Whitehall officials will soon be hunched over a series of internal reports about the economic effects of Brexit to decide which bits can be released in response to pressure from parliament. Whether this controversial advice survives the process of redaction intact or not though, much can already be deduced about its content.

The Brexit secretary, David Davis, has described the 58 impact studies as containing “excruciating detail” on the likely consequences of different departure scenarios. Of particular interest are those that imagine what would happen if Britain leaves the EU single market without a replacement trade deal and relies instead on World Trade Organisation rules.

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A recently-released list of the sector headings – arranged in alphabetical order from advertising and marketing through to wholesale markets and investment banking – makes clear that the civil servants who drew up these studies nearly a year ago left almost no corner of the economy untouched. They include some sectors, such as the automotive industry, which are known to be extremely nervous about the impact of a hard Brexit, and others, such as fisheries, which could stand to benefit.

Accounts vary on whether the analysis amounts to anything genuinely revelatory, or will simply prove embarrassing to a government still insistent that Brexit will be just fine.

“Don’t overestimate what’s in them,” Davis told a Lords select committee on Tuesday, as the campaign for publication reached a crescendo. “They are not economic models of each sector,” he said. “They inform our negotiations, but they are not predictions.”

On the other hand, his Department for Exiting the European Union has also been adamant that publication would not be in the national interest, because it would give away its negotiating position and make it harder for civil servants to give advice in a “safe space”.

In the same parliamentary evidence session this week, Davis said the next stage of talks in Brussels would probably come down to Britain paying large sums of money to maintain future market access. Were his rivals in Brussels to know exactly how much the British government thought failure to reach a deal could cost, they would know better how far they could push negotiations over the divorce settlement.

There is also the fear that the reports contain market-sensitive information about specific companies that could deter them from talking freely about the challenges they face in future.

Though carmakers are known to be nervous, Toyota and Nissan have been extremely secretive about the discussions they have been having about investment decisions for new production lines.

Fortunately for those who favour more transparency, many other businesses have already been publicly vocal about the threat they face from a hard Brexit. Some private sector analysts, such as accountants KPMG, have drawn up their own sectoral analysis which gives a clue to the overall conclusions likely to have been reached in Whitehall.

A KPMG study produced around the same time as the government’s examined 16 broader sectors for their sensitivity to two key factors: access to EU workers and dependency on export markets. Though cruder than the government exercise is likely to have been, it identifies half a dozen that have high exposure in the event of a hard Brexit.

At the top is food and drink, which risks losing restaurant and farm workers at the same time as European exports dry up. Close behind is the pharmaceutical industry, which relies on regulatory harmony with Europe, and a range of manufacturing sectors who could be hit hard by new customs barriers.

For Labour and other transparency campaigners, it is self-evident that people in these industries deserve to know what might happen. The European parliament has also published its own study of risks for other member states. It will be now be down to the British government to decide just how much “excruciating” detail it wants to own up to.