No, it is not normal.
The Government provided two examples of previous reports that each happened to take (A) ten days for the Government to confirm were OK to publish and (B) six weeks for publication. So on average, each activity took ten days and six weeks respectively.
But the PM has not given the OK for this report within ten days, so that delay is not normal.
The report will also not be published within six weeks of it being given to the PM, so in that respect it is not normal either.
Unhelpfully, there has been some conflation of (A) the time for the Prime Minister to confirm there are no classified issues remaining that are prejudicial to the continued discharge of the functions of the agencies and respond that the Intelligence and Security Committee may publish a report, (B) the time to publish such a report and (C) the time for the Government to produce a substantive response to a report.
In terms of this specific report, the Government's position is, with my above categorisations in italicised parentheses:
Because the ISC deals with matters of national security and
intelligence, its reports always contain sensitive information, so it
is entirely right that they go through an intensive security review
before publication. This report is one of a number of ISC reports that
the Government are currently considering. The current length of time
that this report has been with the Government is not unusual, as this
has averaged around (B) six weeks for reports published in recent years,
and (C) three to four weeks for a response to be forthcoming from the
For example, the details of the counter-terrorism review following the
attacks and the 2017-18 annual report were sent together to No. 10 on
12 October 2018. We were asked to respond (A) 10 days later on 26 October.
We responded on 8 November, and then (B) the checked, proofread report was
published on 22 November. Similarly, the details of the detainees
report were sent to No. 10 on 10 May 2018. Again, the ISC asked for a
response within (A) 10 working days on 24 May. We responded on 30 May, and
then (B) the checked, proofread report was published on 12 June. In both
cases, the process took approximately six weeks, because by law it is
imperative that the process is thorough.
In short, (A) a 10 working day period for the Government's response that publication is OK and (B) a six week period for publication itself (i.e. proofreading, printing and laying before both Houses of Parliament whereupon it is made publicly available), which is the ISC's responsibility.
Grieve's position, and that of other members of the ISC who have spoken up, along with other politicians with intelligence and security experience (such as Lord Anderson, the former Independent Reviewer of Terrorism Legislation) is that there is long standing agreement the PM will endeavour to respond within ten days as to whether the report may be published or that time is required to amend it, and the Government has not provided such a response.
Again, the talk of six weeks includes the Committee's time to print the report and prepare for a press conference - it's got nothing to do with the Government. In fact, in this particular case, the ISC says they were ready to publish within the hour of receiving the Government's OK. Grieve et al say the report has been cleared by the intelligence and security agencies (confirmed publicly by the agencies themselves, unusually) and the Cabinet Office and wonder what remains for the PM to clear, having received no explanation.
The Government's counterpoint is:
There is no set timeline within the memorandum of understanding with
the Committee for the Government to clear such reports for
publication, and under the same memorandum there is no set timeline
for a response, nor is such a deadline set in the governing
Now, that is true but of course it doesn't mean a delay is normal or reasonable.
For such a report to be published, it must be laid before the House on a 'sitting day'. Unfortunately, Parliament has been dissolved since 6 November 2019 for the general election on 12 December - therefore there are no sitting days between those dates. And as Parliament has been dissolved, so have all the Committees including the Intelligence and Security Committee. It can take months to reconstitute the ISC - the former ISC took six months to be constituted following the general election in 2017.
Those were factors in the urgency expressed by the ISC - the dissolution of Parliament, the forthcoming general election, and the fact the report or parts of the report might not be timely by the time the ISC is reconstituted.