Belfast Covers. Postage Due?

Grabbed a small lot of covers today. 1930's and 40's Belfast. Couple of censored pieces, some slogan cancels. But I liked the one without the stamp best. Does the T 30 mean 30 cents postage due?

Stampcrow:

30 centimes, I believe. It does not appear that the postage due was collected by the Niagara Falls post office.

Nice inverted "1938" in the second cover!

Best wishes,
AndrewG

As agondocz has already mentioned, it is 30 centimes which was the UPU international "currency" used in postage due calculations at the time. As the letter was posted unpaid (normal rate 1.5 pennies) it was given a double deficit calculation of 3 pence which was converted to T 30 centimes as the rate for UK was 10 centimes = 1 penny. On arrival in USA it would have been converted into US cents which would have been 6 cents (1 US cent = 5 centimes) as indicated by the scribble "6" next to the T mark.
It actually looks like there was a stamp on the cover but it fell off.

Nice 2nd cover. Not only the really unusual inverted date slug, as already noted, but a British Industries Fair slogan cancel, which was the subject of Ikey Pikey's very recent thread https://goscf.com/t/46316

Nice postage due cover. Looks like there was a stamp on there but fell off on it's way to the canceller. Probably postage dued in Belfast (similar ink colour) and sent on its way.

Thanks for the responses. Centimes...of course, not cents. Is the BE underneath the 30, a location? I agree about the loss of the stamp. You can even see the perfs image.

Tim H, thanks for pointing me to that thread. Good links there.

BE = Belfast telegraph code

Thanks again!