The report from the intelligence and security committee into Edward Snowden’s disclosures of GCHQ’s mass surveillance personal data collection programmes paves the way for the introduction of the “snooper’s charter” after the election.

Eighteen months after politicians and spy chiefs condemned Snowden as a traitor and questioned the patriotism of the editor of the Guardian for publishing his disclosures, the intelligence agencies have finally acknowledged the need to “step out of the shadows” and spell out the nature of their intrusive capabilities.

It would be too much to expect any kind of apology from the intelligence and security committee, which under the chairmanship of the tainted Sir Malcolm Rifkind was quick to discredit the Snowden disclosures, for failing to tell the public about what GCHQ has actually been up to all these years.

But it is worth marking the ISC report as perhaps a high-water mark of the impact on the Snowden disclosures on Britain’s intelligence and security services.

The conclusion from the cross-party group of senior MPs and peers on the ISC – who operate “within the ring of secrecy” – that Britain’s complex web of surveillance laws needs replacing with a single act of parliament would never have happened without those disclosures taking place.

Their recommendation that this new legal framework must be based on an explicit avowal of intrusive surveillance capabilities and spell out authorisation procedures, privacy constraints, transparence requirements, targeting criteria and the rest is also significant. The architects of the current 2000 Ripa (Regulation of Investigatory Powers Act) surveillance law would claim they tried to do much the same albeit in a largely pre-digital age.

But perhaps most important change this week has been the ending of the intelligence agencies’ age-old doctrine of “neither confirm, nor deny” when it comes to their work and capabilities.

Former home secretary David Blunkett told the ISC that such “old-fashioned paternalism” – in effect just “trust us” – was no longer enough to command public confidence.

As Sir David Omand, the former head of GCHQ, told the ISC: “The most important thing is to explain how the system actually works and, as importantly, what it does not allow as well as what it does allow.”

The ISC says it agrees and recommends that the new surveillance law should list each intrusive capability available to MI5, MI6 and GCHQ and the human rights obligations that constrain their use.

But that is where the good news ends. For the ISC also sets out very clear limits to this exercise in transparency and that means it won’t be practicable to “specify the detail of certain arrangements in legislation”. Instead, convoluted codes of practice will be published instead.

It is hard to believe reading the ISC report that in the past few weeks GCHQ has twice been found to have been acting unlawfully for the past seven years for failing to disclose the human rights safeguards it employs in its bulk data collection programmes.

A third such ruling is imminent. It may be the MPs and peers regard such privacy rights rulings as “technical” but that only highlights the root of the problem: that they regard privacy as a technicality.

The ISC report may have been written before they were published but one cannot help but speculate that the anticipation of those rulings was a major factor behind this new move towards transparency.

Incidentally, the ISC’s own report is an example of how hollow that commitment is, with its paragraphs regularly punctuated with triple asterisks indicating redactions and undermining some of its key points. Search for Prism or Tempora in the report and you find only the barest passing mentions.

More seriously it won’t tell us what GCHQ is up to in trying to crack web encryption systems despite acknowledging in doing so they expose the public to greater risk and involve potentially serious political and economic ramifications.

All the main political parties agree that Snowden means there needs to be a major overhaul of the surveillance laws after the general election. The Conservatives make no bones about the fact that they want to see the return of the snooper’s charter – the mass surveillance programme that will enable the storage for up to 12 months of the communications data that track everyone’s web and phone use. The Liberal Democrats have said they will oppose such a surveillance programme that logs everyone’s web use, while Labour agrees with them that much tougher oversight is needed.

The ISC report does not explicitly propose the snooper’s charter but it does provide a vehicle for its introduction. Most importantly it rejects the need for a warranted approach to the 500,000 requests for communications data made each year by the police and security services.

The MPs and peers admit that accessing communications data can allow the police and security services to build a richer picture of an individual but maintain it is still less intrusive than reading emails or listening to phone conversations.

“We therefore do not consider that this narrow category of communications data requires the same degree of protection as the full content of a communication,” they conclude.

In doing so they leave the door wide open to the introduction of the snooper’s charter, which involves the mass harvesting of personal communications data and the use of automated data-mining techniques through a “request filter” to sift through the haystack to find the proverbial needles.

The intelligence agencies argue that a breach of privacy only happens when human eyeballs see the selected results, and that no fishing expeditions are allowed.

But it is fairly obvious that if the request filter asks for the IP addresses of all the mobile phones in Trafalgar Square last Thursday at 12.30pm then the results, when matched to their owners, are going to throw up a lot of intrusive answers. They may insist it is only “bulk data collection” but it is clearly a mass surveillance programme in all but name.

The committee members appear to acknowledge this themselves when they argue that any new law should differentiate between basic “comms data” –email addresses, phone numbers, etc – and “comms data plus”, which “could reveal private information about a person’s habits, preferences or lifestyle choices, such as website visited”. This kind of comms data “should attract greater safeguards”, say the MPs, but they don’t elaborate.

Even for more intrusive surveillance, such as reading emails or listening to phonecalls, the ISC rejects demands that at least a judge rather than a minister should be responsible for authorising the warrants. It is hard to see how the US internet giants are going to hand over their customers’ data without such a safeguard.

The ISC also falls down on the demands for stronger oversight. Yes they want to see the current mish-mash of commissioners given more resources, but no extra powers or a powerful inspector-general able to hold them to account.

The foreign secretary, Philip Hammond, said this week that it was time to “draw a line” under the debate about mass surveillance, but this ISC report shows that it is time it got under way in earnest if there is to be an anything like an adequate British response to Snowden’s disclosures.