Two and a half years ago, a British soldier pressed “send” on an email that was to cost taxpayers hundreds of millions of pounds and change the lives of thousands of people.

That email contained the names and details of more than 18,000 people who had applied for asylum under the Afghan resettlement scheme, many of whom would have been obvious targets for reprisals by the Taliban.

Since then, more and more people have come to find out about that leak, and yet the news remained secret until this week, protected by an extraordinary government superinjunction.

Now that the details of the leak and the subsequent secret resettlement scheme are public, questions are turning to who knew what, and when?

2022

February

Military officers ask a soldier working out of special forces headquarters to help verify the names of people who were applying for asylum under the Afghan Relocations and Assistance Policy (Arap).

The soldier sends a spreadsheet containing all 18,000 names to Afghan contacts in the UK, who then pass it on to others in Afghanistan. Officials say the soldier only intended to send 150 names for verification, and did not know the entire database was actually contained on the spreadsheet either in hidden rows or on a hidden tab.

2023

August

The existence of the database, which had remained secret since it was sent, becomes public when one Afghan – who had apparently had their asylum claim refused – threatens on Facebook to release it.

Afghans on the Facebook group alert British contacts, one of whom then emails the then defence minister James Heappey and then shadow defence minister Luke Pollard to tell them of the possible security breach.

The Ministry of Defence then works with officials at the Foreign Office, MI6 and GCHQ to identify the source of the leak. Ministers from various departments meet in the Cobra briefing room along with Gwyn Jenkins, the director of special forces, to discuss their response.

Meanwhile, Afghans contact David Williams, a journalist at the Daily Mail, to tell him about the story. Williams calls the MoD, who urge him to hold off publication until they can investigate further.

On Friday 25 August, Ben Wallace, the outgoing defence secretary, personally applies to the courts for an injunction to prevent the details becoming public. The injunction is supposed to last four months, giving the government time to airlift those affected out of Afghanistan and bring them to the UK.

September

Two days after Grant Shapps becomes defence secretary, the judge Robin Knowles not only grants the injunction, but upgrades it to a superinjunction, meaning that not only can the details of the leak not be reported, but neither can the injunction itself.

November

Officials decide to relocate an initial 150 people affected by the leak from Afghanistan to the UK under the new and top-secret Afghanistan Response Route. The total number to use that route will eventually grow to 6,900 by the time the Labour government shuts it down in July 2025.

December

Heappey briefs John Healey, then shadow defence secretary, about the leak and the response, at the same time making Healey subject to the superinjunction. Healey takes the legal threat so seriously he does not tell his party leader Keir Starmer about it.

Around this time the Speaker of the House of Commons, Lindsay Hoyle, is also made aware of what has happened.

2024

April

The Afghanistan Response Route begins operating.

May

Judge Martin Chamberlain orders the removal of the superinjunction, but the decision is successfully appealed by the government.

October

Having entered government three months earlier, Labour ministers decide to redesign the secret resettlement programme and fold it into the public one.

November

The new government applies to have the superinjunction extended.

During the hearing, Chamberlain asks during the hearing how it can be possible for the government not to reveal the details of what has happened, given it now estimates the total cost of all the Afghan resettlement schemes could reach £7bn. Nevertheless, he grants the application.

2025

January

Six months after winning the election, Labour decides to commission a review into what options it has for the secret resettlement scheme. The commission is to be led by Paul Rimmer, a retired civil servant, and report in “late spring”. Once more, the government successfully applies to extend the superinjunction.

March

The government invites the Conservative party leader, Kemi Badenoch, to a briefing about the leak and the secret relocation scheme, but does not mark it urgent and she does not attend.

June

Rimmer files his report, finding “little evidence of intent by the Taleban [sic] to conduct a campaign of retribution” against those named on the list.

The review adds: “The actual data set (versus some knowledge of ‘data’ being lost) may not have spread nearly as widely as initially feared … We believe it is unlikely the dataset would be the single, or definitive, piece of information enabling or prompting the Taleban to act.”

The government now tells Badenoch it is “urgent” that she is briefed on the situation, but a meeting does not happen until 14 July.

July

On the basis of the Rimmer report, Chamberlain says he is now minded to remove the injunction. Three days later, on 4 July, the government says it is ending the secret relocation scheme and will apply to remove the superinjunction.

Chamberlain orders the superinjunction to be withdrawn on 15 July at midday, giving the government time to contact anyone else affected and take protective measures if necessary.