In a dramatic admission, a senior official with the Scottish Police Federation said it was now commonplace for police vans to operate in a holding pattern - what he called "doing the Heathrow stack with prisoners" - because facilities at stations were full or inadequate.
That comment has laid bare the frustration of ordinary police officers at a lack of spending on infrastructure. But, crucially, it also shows how the important time of ordinary officers - who should be fighting crime on the frontline - is being wasted.
Joe Grant, the general-secretary of the Scottish Police Federation, told MSPs yesterday: "It's a message for Christmastime: instead of no room at the inn, there's no room at the police station."
The comments come as the Scottish Government has signalled its intention to ensure more officers are on the frontline fighting crime. Alex Salmond, the First Minister, has promised an extra 1,000 police for frontline duties through "recruitment, retention and redeployment", but experts warned yesterday there were serious doubts about these measures.
Mr Grant said there were potentially insurmountable barriers to both the retention and the redeployment parts of the package. And Professor Arthur Midwinter, a finance expert, said there was not enough money to hit the recruitment target of 500 new officers as well as meeting police pension liabilities.
To add to the SNP's problems on law and order yesterday, Kenny MacAskill, the justice secretary, admitted he could not force the courts to move from prison terms to community sentences - despite a clear manifesto commitment to bring in a new sentencing regime.
Mr Grant's revelations about the lack of police cells came as he gave evidence to Holyrood's justice committee, warning of the problems police forces were experiencing because of budget pressures.
He told MSPs he knew of one incident, just over a week ago, when a suspect was picked up in Bellshill, Lanarkshire, and, instead of being locked up in a Bellshill police cell, was driven 25 miles to Clydebank in the middle of the night as no other cells were available. The round-trip took two police officers away from the frontline for at least an hour - and possibly longer - when they should have been out on the streets.
Mr Grant added: "We have police vehicles in Strathclyde and other areas circling police offices with prisoners waiting for a space to put someone in."
He told MSPs: "Now, that's a result of insufficiency of capital funding in order to up the volume and the quality of the prisoner-handling areas in that particular force. Those are the real challenges.
"Now make efficiency savings from those, when they are already challenged - that's where the real difficulties lie."
John Wilson, an SNP MSP for Central Scotland, said: "It reminds me of planes circling at Heathrow, waiting to land. That is a vast waste of resources, in terms of manpower, in terms of taking police cars off the streets." He asked: "How frequent is that scenario?"
Mr Grant answered that it was "a fairly frequent occurrence, most clearly in the Strathclyde area, of doing the 'Heathrow stack' with prisoners".
He predicted that the situation would get worse if there were further squeezes on the police budget - a development officers fear is likely if the Scottish Government proceeds with its plan to allow councils greater flexibility on spending.
The SNP has promised an extra 54 million for Scotland's police forces, but that has to be spent on recruiting new officers and finding ways of moving older officers on to the frontline. It also has to be used to cover the increasing pensions bill.
The Scottish Police Federation is worried these developments, plus the Scottish Government's determination to end "ring-fencing" of the police capital budget, will make circumstances for officers on the ground even worse.
The ring-fencing protected the budget for capital projects such as police stations but, if that is removed, councils would be able to use the money for other priorities.
After the committee meeting, Mr Grant said he had a detailed knowledge only of the situation in Strathclyde, but he warned that the "potential exists" for police vehicles to be circling police stations in every city in the country every week. He said: "Could it be suspects of serious assault? Yes. Could it be for theft or housebreaking? Absolutely."
He added that police will "go back to their home station, expecting to lock someone up, saying they have got a prisoner inside their vehicle. If that is full, what you would then do is go to the next nearest, then the next nearest and then the next nearest.
"This is where the real inefficiencies come in: if you have one prisoner, you have two cops in the car. How long does it take to drive from Bellshill to Clydebank, even in the middle of the night, and back again?
"There has been insufficient money available for the refurbishment, modernisation or growth of our custody-holding facilities."
Bill Aitken, the Conservatives' justice spokesman, said: "The Scottish police service is struggling to cope with rising crime and offences, increasing bureaucracy and the thin blue line is stretched to breaking point.
"Too many of our police stations are now only open part-time and this news that police officers - two at a time - are having to drive from police station to police station just to find an empty cell demonstrates the crisis facing the force."
He went on: "The SNP plan to remove ring-fencing from the police capital grant is a retrograde step. Until now, local authorities could give their joint police boards more money. In future, they can choose to give them less and thus make a bad situation critical."
Paul Martin, the Glasgow Springburn Labour MSP, said: "I think there is going to be real, genuine, public concern and alarm that there are dangerous individuals being driven round and round police stations."
Mr Martin said the Scottish Government's budget left "very little headroom" for police forces, and ministers' plans to allow councils to spend money on what they wanted - rather than ring-fencing specific budgets - would put a further squeeze on police finances.
Experts attack flagship plan to recruit an extra 1,000 officers
EVERY aspect of the flagship ministerial plan to try to increase police numbers in Scotland came under attack from experts at Holyrood yesterday.
Alex Salmond, the First Minister, wants to use "recruitment, retention and redeployment" to create an extra 1,000 police officers in Scotland.
But Joe Grant, the general- secretary of the Scottish Police Federation, warned MSPs that there was no more scope for redeployment, with all those officers who could be moved to front line duties having been moved already.
Mr Grant said there were also serious problems with the government's plans for retention - getting more older officers to stay on beyond their retirement date.
He said it would be very difficult to persuade them to stay on, particularly to move back on to the front line, and it would be more expensive than recruiting new officers.
Professor Arthur Midwinter, a finance expert who now works for the Labour Party, then warned that there was not enough new money to recruit the 500 extra officers pledged by the Scottish Government and to pay for the increase in police pension costs, which is due to kick in over the next two years.
The interventions by Mr Grant and Prof Midwinter are the latest in a series of attacks on the Scottish Government's police plans, but they also represent some of the most detailed criticisms so far of the SNP's strategy.
Mr Grant said it cost about 30,000 a year for a new police recruit, but about 45,000 to retain an experienced officer because of higher salaries.
The government's figures for additional officers are all based on the 30,000 figure.
Mr Grant said: "You have to ask - at what cost do you wish to retain these additional skills, experience and knowledge.
"By our estimation it's [an extra] 15,000 per head."
He also warned of the psychological barrier of persuading older officers, who are often employed in back-room duties, to stay on and go back to the front line.
He said they would think: "How am I going to get my head around going back into the cut and thrust?"
Mr Grant said the problems were equally acute for redeployment.
"The reality is that as far as moving officers out of office jobs, that, by and large, has been done and there are very few who can have that title attached to them at this present moment," he said.
Prof Midwinter said it would be very difficult for chief constables to recruit the extra officers and cover increased pension contributions.
"I would see them being able to recruit the 500 officers, but not to meet the pension costs, and by law they have to meet the pension costs.
"It will probably lead to a situation where, in classic fashion, they delay recruiting officers in order to make the budget add up."
Ministers also want the public services to cut 2 per cent of their budgets through efficiency savings.
Prof Midwinter pointed out that, because 70 per cent of police budgets are used up in fixed salaries and pension costs, the police forces were being asked to make all their savings from just a third of their budgets - the equivalent of a 7 per cent saving, not a 2 per cent one.
• THE Nationalist government was last night accused of reneging on another manifesto commitment after Kenny MacAskill, left, the justice secretary said he will not stop judges punishing criminals with short prison sentences.
The party's manifesto gave a clear signal that criminals would no longer be sentenced to six months or less in jail, amid a growing belief that short sentences only cause more reoffending.
"The presumption will be that an offender given a custodial sentence of less than six months will have that sentence turned into an equivalent punishment in the community," it stated.
Since the May election, Mr MacAskill has repeatedly spoken of his desire to rid Scotland's overcrowded jails of "flotsam and jetsam", insisting jail should be used only to lock up dangerous and serious criminals.
But as he launched new community service orders, he admitted he could not force the courts to stop handing out short prison sentences.
"There may be instances where sheriffs feel what is appropriate is a short, sharp sentence. There are instances where it may be appropriate. We, as a government, are not going to interfere in the judiciary," he said.
Mr MacAskill said he hoped that "revitalised" community sentences would encourage courts to force offenders who commit less serious crimes to "pay back" the neighbourhoods they have damaged, rather than simply sending them to "lie around in prison" for a few weeks.
Last night Margaret Smith MSP, the Lib Dem's justice spokeswoman, accused Mr MacAskill of abandoning the manifesto pledge. "The use of the word 'presumption' gives a clear sense to the average man on the street that this is something they will deliver. Clearly, they have now decided they cannot," she said.
Following a review of community penalties, Mr MacAskill said local communities will be given a say on the type of work done by offenders in their area.
Offenders will also have to carry out the work within six months of the sentence being imposed, instead of the present 12 months.
Ministers also propose that community service orders, supervised attendance orders and community reparation orders will be replaced with a new single community service order, ranging from 20 hours to 300 hours.
And, for the first time, community service could include an activity other than unpaid work, such as debt awareness training or support to help offenders into employment.