Plans to close Scotland's busiest custody facility for six months to address overcrowding have been shelved.

An inspection of Edinburgh division's St Leonard's facility in October found it exceeds capacity almost every weekend and requires "significant investment" for upgrades.

Police Scotland's estates department did an initial survey "which has raised concerns regarding timescales, cost and the need to shut the centre for potentially six months whilst improvement works are carried out", according to an update submitted to the Scottish Police Authority (SPA).

However, chief superintendent Garry McEwan, Police Scotland's head of custody division, said: "There are no immediate plans to close custody at St Leonard's now or in the near future to facilitate any of the identified improvements."

Police Scotland is "continuing to work with estates to combine their views architecturally with our operational requirements", he said.

The police inspectorate also called for an urgent review of the safety and security of Edinburgh's prisoner transfer vehicle after custody staff said "they can feel vulnerable" while transferring prisoners.

Mr McEwan said: "The vehicles we are using to transport custodies in the Edinburgh area have been reviewed and are fit for purpose."

In October, HM Inspectorate of Constabulary said: "St Leonard's exceeds its capacity almost every weekend and detainees are transferred as far away as Greenock to centres with vacant cells.

"It is our view that the pressure placed on St Leonard's is not sustainable. Police Scotland is exploring options to alleviate this pressure but these efforts should be expedited."

HMICS added: "If St Leonard's is to continue as the primary custody centre for Edinburgh in the long-term, significant investment is required to upgrade its facilities.

"Improving its facilities requires consideration to be given to our findings regarding perimeter security, the docking area, the layout and size of the charge bar area, sergeant oversight of the booking in process, sightlines generally, the location of emergency alarms, temperature and ventilation, the exercise yard, and showering and kitchen facilities.

"In exploring the options for meeting custody demand in the Edinburgh area, Police Scotland must take a long-term view of the costs and benefits of creating new capacity versus investment in current custody estate."

HMICS continued: "We remain concerned, as do local custody staff, that the vehicle used to transfer detainees from St Leonard's is not suitable for such long journeys.

"There are concerns about the safety and security of the vehicle, the lack of seatbelts and poor ventilation.

"Staff transferring detainees also told us they can feel vulnerable while doing so and feel they lack guidance on what to do if something goes wrong during the journey.

"In the short-term, custody division should urgently assess whether the vehicle used to transfer detainees from St Leonard's on journeys outwith the city is fit for purpose and identify a more suitable vehicle if needed."

Mr McEwan said: "Thousands of people are held in custody in Edinburgh every year and we are committed to ensuring their safety whilst they are under supervision.

"Police Scotland is reviewing arrangements for the provision of custody facilities across Scotland to ensure we continue to support local policing and collectively deliver an effective and efficient service.

"Some improvements are required within the custody suite at St Leonard's and we are currently assessing the best way to carry this out to minimise disruption and ensure operational business as usual.

"There are no immediate plans to close custody at St Leonard's now or in the near future to facilitate any of the identified improvements."