Assistant Commissioner Nick Ephgrave says that the Met is short of experienced traffic officers and skilled investigators for rape cases.

He told the London Assembly’s Police and Crime Committee that the force currently has a vacancy rate of 11% for traffic officers - which would be 6% if officers had not been transferred to the violent crime taskforce to deal with serious violence in the capital.

The traffic unit currently has around 1,500 officers including 520 PCSOs. The Met has resorted to using rest days and overtime to ensure cover.

AC Ephgrave explained why there was a shortage: “Road traffic officers are far more experienced and skilled than the typical officer because they have been around for longer.”

He added the force was making sure officers were not at risk of burnout: “We are carefully monitoring our overtime.”

Road traffic officers were prioritising offenders and locations where incidents such as street racing occurred over general visibility.

AC Ephgrave told committee member Sian Berry (Green Party): “If we had more officers, we could do more of that.”

He also revealed that the specialist team investigating rape cases is running at nearly half strength.

It currently has 140 deployable officers but should have 213. He revealed there are detective constables in the force running 15 cases.

The job involves taking initial statements to taking a victim through the pressures of a court case and requires “quite a mix” of skills, according to AC Ephgrave. He said the welfare of investigating officers also had to be a taken into consideration.

“It is a voluntary role, it has to be the right person. We are currently under strength,” he said. “I’ve done it myself, I know how emotionally stressful it can be.”

Resourcing the investigator role is the focus of the Met’s Gold group. An initial reception officer deals with the victim’s statement and the early stages of the case before a more experienced officer takes over to take it through the criminal justice system.

There have been delays in getting digital evidence from phones and the charging decisions made by the Crown Prosecution Service. There has also been a rise in cases where the victim knew the assailant because more people were reporting assaults by a partner.

AC Ephgrave said: “All of these things have conspired against us. It’s a multi-faceted thing and there are many moving parts.”

But Sophie Linden, the Deputy Mayor for Policing admitted the current outcomes were unacceptable: “Victims are falling out of the system because they aren’t getting the right support.”

AC Ephgrave said work by the Met to resolve the problems that have resulted in the low rate of rape convictions were leading to change.

He said: “I’m comfortable that all of the things I’ve talked about… will come together to help. My people are working their socks off. I do think we are moving in the right direction.”

The meeting also heard that the uplift campaign to recruit more officers had halted plans to sell off police buildings, although the now mothballed Paddington Green station formerly used for terrorist suspects will be sold for development.

Part of the problem was that planning teams were unable to set clear plans as they had no indication of how many officers would be recruited beyond this year’s allocation.

Ms Linden said: “We are still reviewing the estate plan in light of the growth in officer numbers. It’s not going to be ‘this is the estate structure for the next five years’ because we can’t do that at the moment. We don’t know what’s going to happen.”

She added; “It’s difficult; we’ve got to get this right. Once you’ve sold a building, it’s gone, absolutely gone.”

But questions were also asked about the training contract signed with the defence giant Babcock which has also been challenged over its contract to provide training to London Fire Brigade which was signed in 2012.

The firm is overseeing the training of new recruits for the new Policing Education Qualifications Framework (PEQF).

Committee member Andrew Dismore (Lab) questioned how the tender process for the PEQF contract had been run and what was being delivered.

The five year contract – with an option to extend for two further years – will co-ordinate work with the universities delivering academic learning. Officer safety training will remain with Met officers.

Ms Linden said: “We had many people bid for the contract. We did have a competition: my recollection is that the number dwindled. This contract is very, very different. It has gone through a lot of reassurance. One of the reasons the contract did take longer was the element of risk – we are recruiting very quickly.”