Default Heads Up New Release Of Air 81 Files (Trance 6)
 

On National Archives

Trance 1 Open Date: 10-01-2014 AIR 81/1 to AIR 81/316 Inclusive 316 Files 316 Unique References
Trance 2 Open Date: 23/07/2014 AIR 81/317 to AIR 81/1488 Inclusive 1176 Files 1172 Unique References
Trance 3 Open Date: 01/03/2017 AIR 81/1489 to AIR AIR 81/1741 Inclusive 257 Files 253 Unique References
Trance 4 Open Date: 30/06/2017 AIR 81/1742 to AIR 81/3329 Inclusive 1604 Files 1588 Unique References
Trance 5 Open Date: 25/04/2018 AIR 81/3330 to AIR 81/5746 Inclusive 2417 Files 2417 Unique References
Trance 6 Open Date: 01/08/2018 AIR 81/5747 AIR 81/8295 Inclusive 2563 Files 2549 Unique References

Date Range Around April 1941 to August 1941

"Hat Tip to Dennis and Martin"