Councils have slashed spending on CCTV and are operating fewer cameras, according to a new report.

Local authorities in the UK committed at least £277 million to the installation, maintenance and monitoring of the systems between 2012 and 2015, research by campaign group Big Brother Watch found.

However, a previous study found that between 2007 and 2011, councils spent £515m - equivalent to £128m a year - and controlled at least 51,600 CCTV cameras.

The latest findings point to annual spending of £92m from 2012 to 2015 and indicate local authorities oversaw 45,284 cameras as of March last year.

Last year there were warnings that police could find it more difficult to detect crime if councils switch off cameras in order to cut costs amid budget squeezes.

Big Brother Watch welcomed the reduction in spending - but claimed the rationale behind it is "not ideological".

Chief executive Renate Samson said: "Whilst the findings of this report appear encouraging, the reduction in spending may be nothing more than a lull before the storm of more intrusive, biometric or 3D cameras appearing on our streets.

"A measured approach should be taken with any surveillance system. Privacy should always be given as much weight as security."

The report was based on freedom of information requests sent to authorities in England, Scotland, Wales and Northern Ireland. There was a 96% response rate.

It found that between 2012 and 2015, local authorities spent at least £38.2m on installing fixed and mobile CCTV cameras, just under £140m on maintaining cameras and £99m on related wage and salary costs.

The totals were down by 57%, 42% and 47% respectively compared with the previous report, although it covered a period of four years compared with three in the latest study.

Big Brother Watch said CCTV schemes appear to have been scrapped altogether in some parts of the country.

Surveillance camera commissioner Tony Porter, writing in the Big Brother Watch report, said: "Despite the reduction in spending highlighted in this report, I am certain that new and advancing technologies will see further investment by local authorities to deliver new and exciting capabilities.

"The sums of money involved are massive and it's important that those charged with delivering this service get it right."

Britain is seen as having one of the most extensive CCTV networks in the world. A report published in 2013 by the British Security Industry Association estimated that there were around 4.9m cameras in total, with most privately operated.