A leaked Police Scotland report shows two-thirds of public CCTV systems still rely on obsolete analogue technology, with "a major investment" needed for them to "remain viable".

However, uncertainty over who should pay to maintain and upgrade the crumbling system threatens to stall any progress.

New research from within law enforcement shows dramatic differences in the quality and funding of public-space cameras, which are increasingly vital for everything from monitoring traffic problems to catching criminals.

Police Scotland has already signalled that it will no longer foot the entire bill for CCTV in the north-east of Scotland, while paying less than a tenth for the same service in Lanarkshire.

But five years after the Scottish Government said the system was in "crisis", the issue of funding has still not been resolved.

Chief Constable Sir Stephen House said: "CCTV funding is all over the place. The system needs a big input of capital to be updated."

Asked who should pay for the system, Sir Stephen said: "That is something for the Government to run a discussion on.

"In some parts of Scotland there is quite heavy funding from the police authority, in others, not so much."

CCTV technology costs millions of pounds to install and operate annually. However, the footage is used in thousands of criminal cases.

A major report commissioned by Sir Stephen on the state of CCTV in Scotland was never published but a draft sets out huge challenges. "There is a major piece of work required to turn around failing systems and to keep them fit for purpose," it said. "It is evident that a major investment is required in CCTV if it is to remain viable.

"The investment in the past in high-quality analogue cameras and infrastructure is too great to be cast aside all at once. The cost of replacement in its entirety would be prohibitive."

The draft also reveals tensions between funders, despite Government investigations in both 2009 and 2011 urging action. It said: "A number of local authorities have indicated that as it is not their statutory obligation to provide CCTV, and that they see the main benefactor to be the police. In the next round of budgetary cuts, CCTV will be looked at and the possibility remains that funding could be withdrawn."

Police Scotland's share of the bill varies from nothing in the Borders and just five to eight per cent across both North and South Lanarkshire and Ayrshire to 100 per cent in the north-east, according to the draft report.

Police and council insiders acknowledge that CCTV is in danger of "falling between two stools" with everybody agreeing it is a good thing but nobody accepting that it is their core business to run it.

The Scottish Government's 2011 strategy looked to encourage the various bodies providing CCTV on an ad-hoc basis across Scotland to co- operate. It is understood there are those who would like to see a national network, potentially with significant cost savings.

A spokesman for Cosla, the body representing most councils, said: "To secure the necessary capital to update CCTV technology and the ongoing funding required for Scotland's network would need all partners to come together and recognise their stake.

"We are beginning a dialogue with Police Scotland, Scottish Government and others to bottom out how we can work collaboratively to achieve that and maintain a functional CCTV network."

A Scottish Government spokesman said: "Our national strategy for public-space CCTV makes clear that it is the responsibility of police and local authorities to work in partnerships to ensure arrangements are in place that contribute to keeping local communities safe."