THREATS to the UK are increasing in scale, diversity and complexity and a watchdog has warned that delays in obtaining security clearance for officials, including some working on high-risk and high-profile projects, risk hampering government efforts to tackle them.

The National Audit Office (NAO) has highlighted failures to meet targets in vetting officials to work in the most sensitive areas of government.

National security has not been compromised and steps have been taken to address “short-term challenges” in the vetting system, according to the Cabinet Office.

But the NAO said the problems were a particular concern when “government is managing a number of high-risk and high-profile projects”, including Brexit.

The watchdog also noted that there was a “high threat of terrorism” and the UK was a “high-priority target for espionage”.

NAO chief Sir Amyas Morse said: “Considering the pressures facing government, the last thing we need is a non-functioning vetting system.

“An effective system needs to be put in place urgently to ensure the Government is able to use its staff effectively, giving them access to the right information, locations and equipment.”

The NAO’s investigation found the Government’s decision to establish a single vetting provider was not supported by an assessment of the expected benefits, costs and risks.

United Kingdom Security Vetting (UKSV) was established in January last year, taking over from separate systems run by the Ministry of Defence and Foreign Office. In 2016, UKSV’s programme board repeatedly rated risks associated with the merger of the previous two service providers as high.

Whitehall departments soon raised concerns about delays in getting staff approved, with some recruits who needed the more thorough developed vetting (DV) temporarily cleared to work only on less sensitive projects.

The NAO report said: “Delays in vetting have the potential to impact government’s capacity and capability to conduct official business.”

The three most common security clearance levels are the counter terrorist check (CTC), security check (SC) and the more complex DV which allows access to more sensitive information or locations.

In January, the Foreign Office stated that the formation of UKSV had “significantly delayed vetting across departments”.

Meanwhile, the Home Office considered vetting delays to be “a key risk to its ability to increase the number of Border Force staff to work on projects relating to Brexit and the UK border”.

UKSV met its targets for completing non-priority CTC and SC cases for the first time in January 2018, but does not expect to meet its DV target until the end of the year.

In an effort to clear the backlog of DV cases, procedures have been temporarily changed to allow some interviews to be conducted by telephone rather than face-to-face.

UKSV was also said to be failing to meet its targets for “aftercare”, providing ongoing assurance about vetted individuals when their circumstances change.

Meg Hillier, chair of the Commons Public Accounts Committee, commented: “The Government’s security vetting provider’s performance is not good enough.

“Despite spending more on staff than its two previous organisations combined, UKSV has amassed an enormous backlog.

“Delays are impacting government and causing inefficiencies worth an estimated £17 million a year.

“UKSV needs to get its act together quickly, especially as the threats faced by the UK continue to increase.”

A Cabinet Office spokesman said: “National security is our highest priority and at no point has this been compromised by the new vetting service.

“We have already taken steps to address short-term challenges in its introduction, and the NAO has acknowledged timescales are improving and targets are being met.”