The outcome of more than 2,000 divorce cases may have been voided by an error in the online form used to calculate financial settlements, an investigation into the fault has revealed.

In a written statement to parliament, justice minister Shailesh Vara MP (pictured) said that the financial assets of more than 3,600 couples were miscalculated due to the error in the self-assessment form on the Ministry of Justice website.

Those involved in the 2,235 closed cases affected by the error may need to apply to court to reopen or renegotiate different divorce settlements, he said.

The error in the divorce form - Form E - was discovered at the end of last year but had been present on the Ministry of Justice website since at least April 2014. The error left debts out of its automated calculation of settlements.

Vara said: ‘The MoJ was alerted to the fault on 10 December 2015 and a corrected version of the form was put online on 14 December. However the wider implications of the faulty form were not immediately recognised.’

Whereas previously it was assumed the faulty formula was present only between April 2014 and December 2015, Vara revealed that the fault also affected cases between April 2011 and January 2012.

The investigation into the fault showed that of the 36,527 cases that used a version of the form, 10% (3,638) used the faulty calculator.

Vara said that HM Courts & Tribunal Service was able to intervene in 1,403 cases which were still live to make sure the error did not affect the final orders.

He added that the final outcome of the remaining closed cases will not necessarily have been affected by the error, as the form was only part of the material and the information provided by the form is often disputed or superseded by further information introduced during proceedings.

But Vara acknowledged that some may want to set aside or vary their order, and said that there would be no court fee for making such an application.

He said: ‘I have instructed HMCTS to write to all parties in the 2,235 closed cases. The letter expresses our sincere regret for the error, sets out what happened and explains that, although Form E is just one part of the evidence used in their case, there remains a possibility that the error affected the final outcome.’

Vara said that the MoJ is uploading a new version of the form setting out how the calculation of net assets should be made. The ministry will also consider the future of the form as part of its broader court reforms and the automatic calculator function will be disabled during this process.

He added: ‘The failure should not have happened. Divorce proceedings can be very difficult and I sincerely apologise for this situation and any distress it may have caused.’

Solicitor and family law arbitrator Tony Roe pointed out that it is more than a six weeks since the fault came to light, suggesting the review has taken more time and resources than was envisaged.

He added: ‘I am not sure why the minister says that the wider implications of the faulty form were not immediately recognised. It was obvious to specialist family lawyers.

‘Originally, justice secretary Michael Gove said up to 17,000 people might have been affected. That figure now announced is double that.’

He said: ‘Some 1,403 [of the 3,638] cases are still live, so hopefully the issue can be proactively dealt with. The remaining 2,235 files are closed – this is where the real problems could lie – and letters are being sent out to those individuals. Waiving any necessary court fee is one thing but these people will need specialist legal advice over a complex issue and there is no longer legal aid there for them. ‘