Power does not always corrupt but it certainly complicates. Office brings a curious restraint to ministers once so principled in opposition. They must look back fondly to once glad, confident mornings. Then, David Cameron could wail that ‘the Labour Party has given up on civil liberties’. How bright still shone the lamp of liberty even just after the election. The coalition government proceeded to promise legislation to ‘restore freedoms and civil liberties’. This grand pledge brought forth the Protection of Freedoms Bill which, as far as the provisions on surveillance are concerned, is not quite the brave new world that we were promised. It’s an improvement, but not much of one.

You might have guessed that the current legislation governing surveillance - the Regulation of Investigatory Powers Act 2000 (RIPA) - was likely to prove problematic just from reading the act. It provides for scrutiny by no fewer than four bodies: the Interception of Communications Commissioner; the Intelligence Services Commissioner; the Investigatory Powers Tribunal; and the Chief Surveillance Commissioner, depending on the powers used and the bodies concerned. That looks, at best, inelegant and, at worst, confusing. Furthermore, the tribunal and the commissioners only act after the event, except the Chief Surveillance Commissioner in a very small proportion (less than 0.5%) of the most serious cases. It you are subject to surveillance it is likely to be signed off by the body snooping on you or by the secretary of state.

As anyone who has watched the fabulous American TV series The Wire will know, other countries do it differently. A unifying thread in its story was the necessity for the police to obtain a judicial warrant to undertake a wiretap or concealed recording. Baltimore cops become adept at pushing their luck in obtaining evidence that will be admissible in court - up to, and including, effective blackmail of the judge. However, for all its faults, the police work within a judicially structured framework. In this country, all three of the RIPA commissioners are also judges (albeit two are retired) but they are, on the whole, not required to authorise surveillance in advance.

Other countries also have the advantage of somewhat less opaque legislation - our own is very badly drafted. It emerged during the News of the World phone-hacking scandal that the Metropolitan Police Service operated a rather handy (for them) definition of interception of communications which excluded any voice messages accessed after the recipient had listened to them. What is more, it took the European Commission - and not any UK authorities - to object to BT’s link-up with American advertising group Phorm.

The commission referred the UK to the European Court of Justice when no domestic action was taken after BT allegedly breached the privacy of 18,000 of its unsuspecting users to help Phorm focus its targeting efforts. The CPS had declined to prosecute, saying it could be reasonably be argued that any offending was the result of an honest mistake or genuine misunderstanding of the law. The Chief Surveillance Commissioner, no less, saw no difficulty under RIPA with the bugging of conversations between the current shadow minister of justice, Sadiq Khan, and a prisoner constituent, Babar Ahmad. The commissioner noted that such activity ‘does not give rise to interception as defined by the legislation’.

The home secretary changed the guidance. It took the Divisional Court to change the rules to confirm the pretty obvious point that prison managers should not authorise the bugging of privileged conversations between solicitors and prisoner clients. That would be a breach of the provisions of article 8 of the European Convention on Human Rights, the right to private life.

A recent Justice report - Eric Metcalfe’s Freedom from Suspicion: Surveillance Reform for a Digital Age - reveals the astonishing reach of surveillance through contemporary British society. No one knows the total number of CCTV cameras in operation, but it is between two and four million. I once counted 27 between St Paul’s Cathedral and the Law Society in Chancery Lane, less than a mile away. The Automatic Number Plate Recognition programme records the time, date and location of 15 million vehicles a day, storing this information for a minimum of five years.

Around 500,000 requests for communications data are made annually - with around 3,000 to Google alone. Some 2,000 interception warrants and 400 requests for intrusive surveillance are granted in an average year. These include authority to bug around 40 hotel bedrooms. Merseyside Police already use unmanned drones as an ‘eye in the sky’ and the Met want a batch of them for the Olympics.

One of the problems that bedevils UK legislation in this area - as so many - is short-termism. This manifests as a longstanding reluctance of politicians of all parties, once in office, to adopt a clear and principled policy: they just want to respond to the stimulus of the moment. A Conservative government passed the Interception of Communications Act 1985 only after the UK’s lack of legislative authority for phone-tapping was slammed by the European Court of Human Rights in Malone v UK. Labour brought forward RIPA, at least in part, as a response to the decision of Halford v UK where the European Court of Human Rights said the earlier system of scrutiny was so limited that it did not apply to tapping a private police phone system.

The Protection of Freedoms Bill should have been a chance to refashion the system of scrutiny from the bottom up - or even the top down. Alas, the opportunity was not taken. The bill adds two more separate commissioners to an already overflowing pot - one for the retention and use of biometric material, and another for surveillance cameras. It retains the principle of regulation after the event and, in the main, has no truck with prior judicial approval other than for local authorities.

If Labour would dare to take it - which it probably does not since it was the author of RIPA - this creates the space for a continuing call for more comprehensive reform. Whatever the politics, the regulation of surveillance will remain piecemeal and unsatisfactory even after this bright new bill. How murky it all gets when you are in power.

Roger Smith is director of the law reform and human rights organisation Justice