Transmission Delayed Ex Halifax

It is not unusual to see covers from Halifax with a cachet reading "transmission delayed....". As convoys sailed from Halifax roughly each week I was looking for some info as to how long the letters were delayed for. So far I have only seen one suggestion that it was until the convoy had arrived in the UK.

Has anyone any info or a like to any article on this subject

AQ

Are you referring to second world war time frame? If so you should specify.

2nd. WW would make sense. Convoys out of Halifax and Sydney, Nova Scotia in that time period. No doubt the mail was delayed.

Sorry I should have been much more specific. I knew what I wanted to find out but did not make it clear

Yes WW2.

The two line cachet
TRANSMISSION DELAYED / FOR PURPOSES OF SECURITY
is not uncommon on mail from Halifax. However it is not found on all mail. The 2 examples I have are postmarked just prior to the sailing date for a HX convoy to the UK but are addressed to the USA. You presumably would not expect this cachet on mail to the UK.

I understand that the mail could be delayed until any info it may have contained about a convoy would be out of date but as convoys left every week or so I woundered how long the security delay may have been. I cannot find any info on the internet.

Sorry for the original confusion

AQ