A review of the UK government's delayed emergency services network intended to replace the national radio infrastructure with a 4G network has itself been delayed by more than half a year.

The hugely ambitious project will see the £2.9bn Motorola-owned Airwave contract switched off at the end of 2019 and replaced by the £1.2bn 4G EE-run network.

However, it has already been hit by a nine-month delay, with Parliament's Public Accounts Committee chair Meg Hillier previously warning "the stakes in this programme are extremely high".

Speaking at a progress update to the committee yesterday, Joanna Davinson, chief data officer at the Home Office, said the department will complete its review of the programme in July. That report, which will reveal any further delays, was due to be published in January.

Davinson was previously vice president at IBM before joining Whitehall in November. She said: "I appreciate that is longer than we had said previously but I think one of the things I brought in with my experience of having run large programmes before, is that in doing these kinds of 'resets' it is really important to bottom out the detail and really understand where those dependencies lie."

The chief said the Home Office would give some users earlier access to the network's data services such as the ambulance services – meaning they could be using two separate devices for voice and data.

The ESN network is intended to reach 97 per cent coverage of the UK, including the extended service and the 250 new sites being funded directly by the department.

The Home Office's Stephen Webb, senior responsible owner of the Emergency Services Mobile Communications Programme, said there were some problems in some of the specialist areas, such as the metro areas outside London, but build-out of the masts in remote areas has "proceeded reasonably well".

"The extended areas we are building are slightly behind the original timescale… they were to be done by mid-June now we're talking end of 2018."

Webb said some areas remain difficult, such as how the in-vehicle solutions will work.

Motorola had previously told the PAC it would not be able to keep Airwave running beyond March 2020, when Vodafone scraps the old Cable & Wireless system.

MPs heard that a contingency plan has been negotiated with Vodafone –Motorola’s subcontractor – "at no extra cost" to the department.

Vodafone has separately written to MPs expressing its concern over its access to the newly built EE infrastructure, claiming that the contract could be in breach in EU state aid rules.

Webb said: “Vodafone have their own interpretation of state aid; we believe EE are very aware of their obligations, as are we.” ®