A £60m police IT project has suffered another major setback after the initial roll-out in December was put back due to technical defects.

An email last week revealed that the first “go live” date for the troubled i6 programme has been shelved as key parts of the system are not working as planned.

The i6 project, dubbed the “largest and most significant transformational change” ever undertaken by the single force, will replace 135 existing IT and paper based systems for use by around 20,000 officers and staff.

Private company Accenture is being paid around £40million to provide the new integrated system but costs may rise to nearly £60m.

Project outcomes include providing organisational “agility” and it is based on a system delivered to 80,000 officers in the Guardia Civil – Spain’s national police force.

However, the scheme has been marked by setbacks, delays and disputes with the contractor.

Neil Richardson, a deputy chief constable at Police Scotland, said the project was the “most difficult” thing he had ever been involved in.

Delivery was supposed to include a partial ‘go live’ roll out in December, followed by i6 being available to all staff next year.

However, an email on Thursday to stakeholders from Superintendent Lynne Hutchinson, who works on i6, has made clear December will not happen: “Whilst both Police Scotland and Accenture have made every effort to achieve the 7th December go-live…a delay to the scheduled go-live is inevitable to allow key issues to be addressed before the system goes live.”

She wrote that the decision had not been “taken lightly”, but noted that a “number of factors” had contributed to the delay.

This included a “larger number of defects than expected” being found and problems in key areas such as Criminal Justice, Audit and Search.

Hutchison added: “Any delay to implementation is disappointing but it is right that any issues are addressed at this stage through work with Accenture to ensure the solution is fully fit for purpose before implementation.”

A revised go-live date has not been finalised.

A policing source said the national roll-out next September – three and a half years after the single force came into being - has little chance of being met.

The initial roll out was supposed to occur in July this year, but was pushed back to September and then December.

It is understood Justice Secretary Michael Matheson was briefed on the latest delay earlier this week.

Labour MSP Graeme Pearson, a former senior police officer, said: “Operational officers depend on systems to enable them to do the work. After nearly a decade of work on i6 there must be an independent external review to find out what has gone wrong here. Why are police officers running an IT project and not the Scottish Police Authority IT director?”

He added: “What is the total cost forecast for i6? How much has already been paid in total to Accenture and all other contractors?”

Alison McInnes MSP, the justice spokesperson for the Scottish Liberal Democrats said: "The police are right to want the system to work properly. But we now see another delay just days after we were assured it was on track. This looks like another part of the centralisation of the police that is not living up to the promise.”