A report into the future of Scotland's police service has strengthened the case for a single force, Justice Secretary Kenny McAskill has claimed.
Mr MacAskill said savings of £153m a year could be achieved, but insisted no decision will be made before the Holyrood election on May 5.
Both the SNP and Labour have come out in favour of merging Scotland's eight police forces, but the move is opposed by the Scottish Liberal Democrats.
Mr MacAskill's comments followed a meeting of the Scottish Policing Board in Edinburgh where the report, compiled by senior police officers and "financial specialists" from all forces, was discussed.
The report described a single force as the least complex and most efficient of the three options put out for consultation by the SNP administration.
The idea of scrapping the current eight-force model is backed by Strathclyde Police Chief Constable Stephen House but opposed by others, including the top officer in Grampian.
Other options include making savings based on the existing system or moving to a slimmed-down regional model.
Such a regional system would be "complex", the report found, while retaining all eight forces was described as "unsustainable".
To make savings of about £153m each year would cost £92m over the lifetime of the reform programme, the report added.
Mr MacAskill said: "This piece of work represents a significant step forward in the evidence base for reform of our police service and does strengthen the case for a single force.
"It identifies savings of up to £153 million a year and some of the costs identified would be incurred anyway, regardless of the structure."
Liberal Democrat justice spokesman Robert Brown said: "I want the current consultation to be stopped and an independent inquiry into the future needs of the Scottish Police Service started after the Scottish elections."