I’m aware of the existence of a concessionary postage rate for Irish charities pre 1840 but am struggling to find any details. Can anyone please help?

Could they (the Commissioners) of some charities, whether in Ireland or the rest of the UK, be covered by Class X of the Postage Act 1837 (1 Vict c.35, 12th July 1837) and its predecessors prior to 1837, so be eligible to receive and send letters by the post free from the Duty of Postage?

Hello Winston and thanks for your reply. I’ve just acquired a turned cover sent between Dublin and Glasslough at a prepaid rate of 2d each way (scans attached). As far as I’m aware the Irish Charities Rate was a flat rate rather than free franking, akin to the Soldiers and Sailors 1d rate, but I’d like to know more such as when it started, who qualified, did rates change over time etc. Some information is helpfully printed on the cover but hopefully there’s more out there somewhere.

see the Post Office Act 1832
(2 Will 4 c.15, 24th March 1832)
XXXI. And be it further enacted, That it shall and may be lawful to and for the Postmaster General for the Time being, from Time to Time and at any Time during the Space of Two Years from and after the passing of this Act, to nominate and appoint all and every such Charitable Institutions or Societies in Ireland as the Postmaster General may in his Discretion deem it expedient should be permitted to send Letters and Packets relating solely to the Business of such Institutions or Societies, by Post, in Ireland, at a reduced Rate of Postage, with full Power for the Postmaster General for the Time being from Time to Time to revoke and annul any such Nomination or Appointment, and the Privilege thereby conferred.
XXXII. And be it further enacted, That it shall and may be lawful to and for the Postmaster General for the Time being, and his or their Deputy or Deputies, Servants or Agents, to and for the Use of His Majesty, His Heirs and Successors, to demand, have, receive, and take for the Postage and Conveyance of all Letters or Packets which shall relate solely and exclusively to the Affairs or Business of any such Charitable Institution or Society in Ireland so from Time to Time to be nominated or appointed by the Postmaster General for the Time being as aforesaid, and which shall at any Time within Two Years from and after the passing of this Act be delivered into any Post Office in Ireland, folded and directed, but without any Seal or Wafer or other Matter to close or fasten the same, and shall be carried, conveyed, or sent Post from the General Post Office in Dublin to the several Post Towns in Ireland, and from the several Post Towns in Ireland to the General Post Office in Dublin, at the Rate or Sum of Two-pence for every such Letter or Packet; provided all and every such Letters and Packets shall relate solely and exclusively to the Charitable Institution or Society by or from which the same shall be forwarded, and shall be superscribed on the Outside thereof in such Manner in all respects as the Postmaster General for the Time being may, in his Discretion, from Time to Time appoint; provided the said Letters or Packets shall contain no Cash, Bank Note, Bill of Exchange, Promissory Note, Draft, or Order for the Payment of Money, or other valuable Security, and shall contain no Writing, Communication, Matter, or Thing whatever other than on the Business of the Charitable Society or Institution by or from which the same shall be forwarded, and provided that no such Letter or Packet shall exceed the Weight of an Ounce.

Well found. Makes excellent sense.

The GBPS website has a link to The 19th Report of Commissioners of Inquiry
into the Collection and Management of the Revenue, Post Office Revenue,
United Kingdom: Part II – Ireland of 1829

https://www.gbps.org.uk/information/sources/parliamentary-reports/Reports from Commissioners of Revenue Inquiry - 19th (Post Office Ireland, 1829).pdf

At page 86 the report states:
"various religious and charitable societies in Ireland, about twenty-five
in number, are also permitted, without authority by Act of Parliament, to
circulate letters, books and papers free from postage"
and I see at Page 88 that the report states "we conceive that the deviation
from the law should have been limited in its object and duration".

So subsequent to that report, the 2d rate must have been put into law by the 1832 act.

A belated thank you to you both for your interesting and comprehensive replies. Can I also add that I have recently discovered a booklet ‘Irish Postal Rates Before 1840’ published by FAI, a German society for collectors of Ireland ( bilingual German / English) which states that the Charity Letter system was introduced in 1819, the first twelve being charged 1d each and the remainder at 1d a dozen! These arrangements were then superseded in 1832 as you state with the 2d rate.

I actually read the 1819 Act as charging an initial 1d in total for up to 12 items and then if there are extra items 1d for each further complete 12 and if the total number isn't divisible by 12 a 1d for the remainder.
A copy of the Act is on this website under the name Post Office (Ireland) Act 1819.

Thanks to you both for the extra info & feedback. Always nice to see.