Scotland's new national police force is facing a shortfall of about £70m next year, its chief constable has revealed.
But the budget for 2013-14 is "do-able" and there is a series of options to be considered about how to "bridge the gap", said Stephen House, Chief Constable of the Police Service of Scotland.
Funds of £1.2bn have been allocated for the police force for next year.
Mr House, who will lead the new force when it comes into operation in April, said the budget is a "challenge we will meet". He spoke out as he answered questions about the budget from MSPs on the Holyrood's Justice Committee.
He said: "My mind is focused on one figure which is the gap between what we believe we are getting terms of funding and what we believe we need. At the moment we're estimating it's about £69-£70m for next year and probably about the same again the following year.
"Moving forward, leading the organisation, I'm looking at the gap between the budget and what we think it will cost to run the organisation at the moment. That's about £70m. We're seeing a challenge there but we think it is a challenge we will meet."
The budget is "tight" but he could live with it, Mr House said.
"I would rather have more money but do I think it's liveable with? Yes."
The budget for 2013-14 is "do-able" and is based on his experience as Chief Constable of Strathclyde Police which, in the past few years, "achieved significant improvements in performance and reduced budgets at the same time".
Mr House has already warned that merging Scotland's eight police forces into one could mean the loss of up to 3000 support staff. But that is the "absolute upper limit" of what the job losses would be.
The new force is first looking to make "non-staff savings".
He said: "Every pound we can save in non-staff expenses and costs is a pound we don't have to take out of support staff."
There is no widespread plan to use police officers to take the place of civilian support staff, known as back-filling, he said. This is a "bad thing" which "should be avoided".
He told the committee: "It may be happening in individual cases and isolated occasions but I'm not aware of it happening as a set strategy anywhere in Scotland.
"There are proposals that civilian staff will have to go to make savings, a level of that is inevitable. But I would not be supportive of something which says 'get rid of a whole section of civilian staff, they are going to go under voluntary redundancy, and we are going to back-fill with police officers'.
"That's not something at this moment in time I believe we need to do. There is no strategy to back-fill with police officers. I don't support any policy which is based purely upon civilian staff going and wholesale back-filling with police officers."
Earlier the committee took evidence from the Association of Chief Police Officers in Scotland (Acpos), the Association of Scottish Police Superintendents (ASPS), Unison Scotland and the Scottish Police Federation.
Chief constable Kevin Smith, president of Acpos, said the financial challenges facing the new single force are "even more significant than we had perhaps anticipated".
He said: "In terms of the savings of reform for next year, what was anticipated as £41m is, in our view, closer to £71m and, for the following year, moving up to £88m is probably closer to £140m."
Commenting on back-filling of police officers into civilian jobs, Mr Smith said: "I think within this whole debate there has been a concern, because of the focus on police staff job cuts, that that may come with the threat of police officers being taken off the street to fill these posts.
"Whilst that is something we would want to avoid, it is, I suppose, something that has to be considered as we move ahead into the coming year.
"That is being candid and honest about one of the potential threats in the coming years."
There would be operational and financial implications of back-filling, and it would be "more expensive for a cop to be in doing a job of a member of support staff who is generally paid less".
Dave Watson, Scottish organiser for Unison Scotland, said the political target of maintaining police officer numbers at 17,234 means that the bulk of savings would be focused on police civilian staff.
"The only way that is going to be achieved, it is perfectly clear in documentation, is by substituting police officers for those police civilian roles," he said.
"The challenges would be easier if [the chief constable] were freed up from that target and allowed to set the right balance of staffing between police officers and police staff."
Chief Superintendent David O'Connor, president of the ASPS, said: "There is a view among some of our members that the figure 17,234 actually puts the chief constable in a straitjacket.
"Don't get me wrong, I would never advocate for a reduction in police officers but I sense, as we actually go forward, the chief constable must be empowered to look at that ... and strike the right balance for the people of Scotland."
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