The director of the Serious Fraud Office has called for reform of disclosure rules to ‘rebalance the system for victims and justice’ following a series of high-profile errors by the watchdog.

Lisa Osofsky said disclosure is ‘one of the biggest challenges’ the agency faces, but added that ‘there is a lot of work happening within the SFO to support our disclosure officers and to make our processes, policies and procedures better’.

Speaking at the Cambridge International Symposium on Economic Crime, she suggested that the current disclosure regime – which was ‘designed before the advent of mass digital data … when there was far less material for investigators and prosecutors to deal with’ – is out of date.

The SFO deals with ‘many millions’ of documents, including ‘complex digital data across many different devices’, in any given case which ‘could fill up 22 London buses’ if they were printed out, Osofsky said yesterday.

‘Yet the regime still demands manual review and description of documents,’ she said. ‘This can take years, with victims waiting for a resolution, waiting for their day in court.

‘The system also runs a deep risk of human error. Despite requiring the manual review of each document, the defence can use a mistake – which is capable of correction – to mount tactical challenges to our cases.’

Her comments come after the SFO was heavily criticised by the Court of Appeal, which has now quashed the convictions of three of the four men who were jailed after the watchdog’s Unaoil bribery investigation over ‘serious’ disclosure failures.

Osofsky and other senior SFO officials engaged in ‘wholly inappropriate’ contacts with David Tinsley, a former US Drug Enforcement Administration agent who was acting on behalf of the family behind Unaoil, the Court of Appeal found.

She also referred in her speech to the collapse of the case against two former directors of outsourcing giant Serco, which prompted an independent review that found ‘systemic problems of real concern’ with the watchdog’s disclosure processes.

She told the symposium: ‘One of my big priorities for the year ahead is that we recognise the significant challenges of disclosure for law enforcement in data-rich, document-heavy cases and rebalance the system for victims and justice.’

Osofsky added that she will ‘broaden the use of tech across our work to enable our staff to deliver their specialist roles with better tools and greater support’.

Meanwhile, solicitor general Edward Timpson today gave details of Tinsley’s previously-reported meeting with the then attorney general Sir Geoffrey Cox QC in October 2018, shortly after Tinsley first contacted Osofsky.

Cox met Tinsley ‘for 20 minutes in the waiting room of his barristers’ chambers … after an acquaintance requested that he meet informally with an unnamed contact with links to the US government’, Timpson said in response to a question from shadow attorney general Emily Thornberry.

He added: ‘It transpired that Mr Tinsley wished to draw the then attorney general’s attention to the value of his services and those of his company in facilitating a better working relationship between the English investigation and prosecution authorities and US authorities.

‘The then attorney general brought the meeting to an end, pointing out that he did not have responsibility for the issues Mr Tinsley had raised.

‘Neither the Serious Fraud Office’s investigation into Unaoil, Mr Tinsley’s involvement in it, nor the defendants in that case or any other case, were raised in the meeting or discussed.

‘The then attorney general took no action in connection with the meeting and had no further contact with Mr Tinsley.’