The Office of the Surveillance Commissioner, which is headed by the former Court of Appeal judge Sir Christopher Rose, is facing an "unacceptable" cut to its annual £1.8million funding.

He was appointed by the Prime Minister to scrutinise the surveillance activities of police, councils and other public bodies. It has been reported that he has already met Home Secretary Theresa May to warn that his organisation will be unable to do its job properly if the cut goes ahead, and he is understood to be preparing to raise the issue directly with David Cameron.

Ministers have repeatedly vowed to curb excessive state surveillance. Only days ago, Mrs May unveiled the new "Protection of Freedoms" Bill, with revised rules on DNA retention, anti-paedophile vetting and CCTV and "snooping" by town hall staff.

The proposed cut to the surveillance watchdog would severely limit the extent of checks on police activities and increase the risk of abuses going undetected. The cut is understood to amount to several hundred thousand pounds. The watchdog's latest annual report, for 2009/10, shows it spent £1.73million of its £1.83 million budget and the team is understood to be asking for a similar figure this year.

They check legal documentation prepared by police and other organisations to ensure that any surveillance or "property interference" is lawful, necessary and proportionate. Last year's report shows they uncovered 78 breaches of the rules in 12 months.

Although it is debatable how effective Office of the Surveillance Commissioner was, it is clear that it is only going to be less effective now, thus allowing the police greater ability to monitor us.