Police Scotland has not made all of the improvements recommended following the deaths of a young couple on the M9.

Lamara Bell and her boyfriend John Yuill suffered fatal injuries when their car crashed off the M9 motorway near Stirling on July 5, 2015.

An inquiry into Police Scotland's handling of the incident uncovered serious flaws in the way it dealt with 999 and 101 calls and led the force to delay the closure of its regional control rooms.

Her Majesty's Inspectorate of Constabulary in Scotland (HMICS) made 30 recommendations for improvements as part of its review.

More than a year on, Police Scotland has admitted only 16 have been fully addressed, with the rest partly met or unmet.

In a report to the Scottish Police Authority published on Thursday, assistant chief constable John Hawkins said: "Police Scotland and C3 division [the force's call-handling section] have, since the recommendations were received, been resolutely committed to delivering the improvements required and successfully implementing each of the recommendations."

Police call centres in Aberdeen and Inverness were expected to shut by the end of 2016 but in August the force delayed the closures until next year as a result of HMICS's report.

It found the crash that caused the deaths of Ms Bell and Mr Yuill was reported to police on the day of the accident but the call was not logged.

The couple's car was not found until three days later. Mr Yuill is believed to have died on impact, while Ms Bell survived the crash and later died in hospital.

Police Scotland's Aberdeen call centre is now scheduled to shut in March, while Inverness will close in June, leaving all 999 and 101 calls to be answered in the central belt.

Its Dundee call centre is expected to shut in December, replaced by a control room responsible for sending officers to incidents after calls are answered in Glasgow, Midlothian, and Motherwell.

In the meantime, some 101 calls will be redirected to the central belt to help the force cope with staff shortages in Aberdeen.