Thanks for the attachment – it makes interesting reading! For those who would like to dig further, there is a lot more official documentation in the public domain, some of it released as recently as 2018. There are 27 files on this accident which are accessible by the public at The National Archives (TNA):
AVIA 101/208 thru AVIA 101/226, plus:
AVIA 13/1383
AVIA 6/23898
DR 11/51
DR 16/142
HO 287/2146/1
HO 287/2146/2
MEPO 2/11089
MEPO 2/11090
There are a further three TNA files which are closed: HO 287/2146/3 Closed extracts: 271 pages Closed til 01/01/2069 MEPO 2/11089/1 Closed extracts: 478 pages Closed til 01/01/2069 MEPO 2/11090/1 Closed extracts: 292 pages Closed til 01/01/2066 As far as I can see, none of these files are ‘classified’ – even the closed ones (where even ‘unclassified’ would qualify as a classified file). In the case of the three closed files, (whose legal status is “Public Record(s)” they are closed for various periods of time due to a variety of reasons, which include ‘Law enforcement’; ‘Health and Safety’; ‘Personal information where the applicant is a 3rd party’; and ‘Information provided in confidence’. From the above, it would appear that the best effort has been made in making the remainder of the Home Office and Metropolitan Police files accessible to the public and it is apparent from the ‘reasons for closure’ why some of this information might still be best kept from public eyes.