A detonation on alleged Russian interference in UK democracy will not be published until after the referendum.
It has gone through the standard security clearance process, but sources say No 10 is cubicle on releasing it.
Ex-terrorism watchdog Lord Anderson said any further hold off would “invite suspicion” of the government’s motives in the run-up to next month’s referendum.
Ministers said the report would be published “in due course” in line with gates for “sensitive” information.
The report examines Russian activity including depositions of espionage, subversion and interference in elections.
The BBC’s Mark Urban said the hesitate would increase concerns the report would be “buried”.
The report, erased by Parliament’s Intelligence and Security Committee, was finalised in March and referred to No 10 on 17 October.
In any case, approval for its publication has yet to be given and this now looks highly unlikely previous Parliament is dissolved on Tuesday.
The chairman of the committee, Dominic Grieve, speaks there is no legitimate reason for delaying it and that voters have a lucid to see its conclusions before they go to the polls on 12 December.
“We continue to be remarkably disappointed by the failure of the government to publish this report and to provide any justification as to why it should not be published. Explanations currently advanced that the timing are too succinct are entirely disingenuous and grossly misleading,” he told the BBC.
The report includes testimony from UK intelligence services such as GCHQ, MI5 and MI6 concerning covert Russian try ons to influence the outcome of the 2016 EU referendum and 2017 general election.
Several MPs and peers believe No 10 is sitting on the report for factional reasons ahead of the election.
Raising the issue in the Lords, Lord Anderson, the latest reviewer of anti-terrorism legislation, said concerns over security could not be inured to as an excuse for non-publication as all the necessary redactions had taken place.
“This unjustified into the deep-freeze undermines the ISC, it invites suspicion of the government and its motives. Will the minister craving No 10 to think again?”
The former head of the Exotic Office, Lord Ricketts, said claims that the government requisite time to respond was a red herring given that it had 60 days in which to do so answerable to existing conventions.
He said there was a “clear public interest” for broadsheet “in the national security implications of Russia’s adversarial conduct”.
The BBC understands that, if erstwhile practice was followed, the report will have been vetted by the news agencies before being referred to Downing Street.
People casual with the committee’s workings say 10 days should have been good enough for it to be “cleared”.
Mr Grieve said the report was highly relevant given the proportion of Russian interference in elections in other countries, notably the 2016 US Presidential selection.
But Earl Howe said the established protocols had to be followed and there was no turns out that for “accelerating” the report’s release.
“The length of time the government has had this promulgate is not at all unusual,” he told the Lords. “The prime minister is entitled to take his landscape on what the report contains.”
But he added: “Having said all that, I do conceive of that the subject of this report is a matter of particular public interest. And I pull someones leg no doubt that level Lords comments will not be lost on those in Figure 10.”