Scotland's police chief has insisted he will not resign over a blunder which left two young car crash victims in the damaged vehicle for three days after their accident.

Sir Stephen House's comments follows growing pressure on the force after the deaths of John Yuill, 28, and his partner Lamara Bell, 25, on the M9, near Bannockburn, after an initial call to police was not logged and officers were not sent out to the scene.

Scottish Liberal Democrat leader Willie Rennie yesterday called for the immediate suspension Police Scotland's control room and service centre closure programme until a review of police call handling is complete.

Mr Yuill was found dead in blue Renault Clio and Ms Bell died on Sunday after being found badly injured by police after a second call last Wednesday. They had been reported missing, after leaving friends and driving off from Loch Earn.

Sir Stephen, who has indicated he will not reapply for the post again next year, said he would not resign at this stage.

He said: "If I come to the conclusion that I should resign then I will resign.

"I don't believe that's the case at this moment in time. The organisation needs leadership."

Mr Rennie had previously raised concerns and a second probe was called by Justice Secretary Michael Matheson to be held by Her Majesty's Inspectorate of Constabulary in Scotland.

It comes alongside the Police Investigations and Review Commissioner's investigation into the incident.

Mr Rennie broached problems at police control rooms before and has been contacted by serving officers and civilian staff with concerns over workload pressures and other issues.

Doors have already shut at Glenrothes, Dumfries, Stirling and Pitt Street (Glasgow) control rooms and service centres. Aberdeen and Inverness are also set to lose their control rooms in September and December 2015 respectively.

In a letter received by the Scottish Liberal Democrats on July 2 the Chief Constable, Sir Stephen House, said "these timescales remained valid".

Mr Rennie said: "Shortages of civilian staff have forced police officers to backfill and cover call centre shifts and people have faced extended waits to have their calls answered.

"These are very serious issues and there is a strong case for the immediate suspension of the ongoing control room closure program until we get to the bottom of the problems in the system.

"At FMQs in March, the First Minister promised that she would discuss these issues with the Chief Constable and the Justice Secretary.

"But it seems clear that the problems that were identified then have not been addressed.

"I am certain the HMICS review will establish what representations the First Minister and Justice Secretary made to Police Scotland and what steps were taken to improve call handling as a result."

First Minister Nicola Sturgeon said: "It is absolutely essential that police Scotland is accountable when things go wrong there is full transparency and accountability and a determination to learn lessons and that's what happening with this incident."

Meanwhile, the man who made the initial call to police after spotting the Clio off the road has spoken of his guilt that he did not follow it up.

However, the man, who wishes to remain anonymous, told the BBC the officer he dealt with was not dismissive and sounded as though he knew what he was doing.

He added that details were taken of the location and he assumed they would check it out. He added: there was "nothing to suggest they would not take it seriously."

He became concerned on the Monday and Tuesday when the car was still there with no police tape covering it, but thought it "must be awaiting recovery".

He said he was "aware of what was being said about whether he should have done more" but believed police were handling it.

Ms Bell's brother Martin has been updating friends and family and thanked the community in the Falkirk and Camelon for helping raise funds and offering support after the tragedy.

He said: "I'm blown away by the effort and time our community in Falkirk are putting into making the loss of my sister as painless as possible for my family.

"There has been two donation pages been set up one for my family and John's family for any funeral.

"Just feels like a bad dream right now...but all your kind words and efforts are helping."