The shift to electronic systems will mean the blunder that saw 709,000 items of medical correspondence not delivered is “unlikely” to occur again, according to the health secretary.

Jeremy Hunt faced an urgent question about the debacle in the House of Commons on Tuesday, following the publication of a damning National Audit Office (NAO) report that said at least 1,700 cases of potential patient harm have been identified, with investigations continuing.

“[It is] unlikely this will happen again because this is about paper correspondence”, said Hunt, who said the NHS is “recently moving all the transfers of communication to electronic systems”.

The NAO report said it expects the figures of potential patient harm to rise from 1,788 as a third of GPs still have not returned their findings from the investigation.

Hunt emphasised the importance of digital records, but added paper still forms an important back up.

“The future is to transport patient records securely over electronic systems. It’s much quicker and there’s much less room for error, but you do also need the back up systems.”

Hunt was grilled in the Commons over the shambles that saw hundreds of thousands of undelivered letters and clinical correspondence pile up in NHS warehouses over a five-year period, including child protection notes, medical records and changes to medication, left languishing in a warehouse.

NHS Shared Business Services (NHS SBS) was contractually obliged to provide the service, but during 2011 and March 2016 a backlog built up, where it increased from 8,000 to 435,000 items. The final figure of 709,000 was confirmed when more boxes were found.

Hunt said the investigation into the scandal will be completed by Christmas 2017.

Jonathan Ashworth, Labour MP for Leicester South, described the stacking up of medical mail as an “absolute scandal”.

Speaking in the Commons Ashworth described the incident as a: “Shambolic catalogue of failure that took place on the secretary of state’s watch.”

Hunt admitted that “what happened at SBS was totally unacceptable”, and said that better assurances on contracts being delivered needed to be guaranteed.

It was reported in the NAO’s publication that NHS England estimated the administration costs alone will be £6.6 million.

Hunt said SBS will be “paying their fair share of the costs that has been incurred as a result of this wholly regrettable incident”.

An investigation by the Information Commissioner’s Office (ICO) is on-going, and the independent authority provided a statement to Digital Health News that said:

“The ICO is currently monitoring the remedial action taken by the NHS to resolve the historic problems. Our investigation is ongoing and as part of that will be to consider a clinical review which is expected later this year.”

NHS SBS is co-owned by the Department of Health and the French company Sopra Steria. Its main business is managing supplier contracts on the behalf of the NHS with revenues of about £87 million for these services.

The Department of Health has a 49.99% share in the NHS SBS.