The Britannia, after being used in the merchant trade between London and Bengal, was engaged as a convict ship. She arrived at Portsmouth on 5 October 1796 and remained there probably loading provisions and making other arrangements before proceeding to Cork to embark the convicts.
The prisoners came from counties throughout Ireland. They may have been held in county gaols before being sent to city prisons......
The Belfast Newsletter reported on the conveyance of prisoners at Dublin on 11th August 1796 -
Yesterday, 68 person under the rule of transportation, confined in the New Prison, many of whom were transmitted from gaols in the country, were put on board a vessel at the North Wall to be brought down to Cork, and from thence are to be sent to Botany Bay 
The Britannia was the next convict ship to leave Ireland after the departure of the Marquis Cornwallis in August 1795. The Britannia departed on 10 December 1796 with 144 male and 44 female prisoners.
Surgeon Augustus Beyer
Augustus Beyer's appointment to the Britannia was at the last minute:
Lord Castlereagh to Under Secretary King.... Dublin Castle 18th September 1797 (Extract), I beg leave to observe that the person appointed here to go out as surgeon to the convicts in the Britannia declined to proceed on the voyage just as the vessel was ready to sail, and the business was undertaken by a Mr. Beyer, who came from England to Cork in that ship, and who, it was represented, had gone two voyages to Port Jackson with convicts with great success
The harrowing story of the voyage of the Britannia to New South Wales under Captain Thomas Dennott and surgeon Augustus Beyer is told in Charles Bateson's The Convict Ships.....
As in the Second Fleet transport Neptune, the combination of a callous and brutal master and a weak, incompetent surgeon made the voyage of the first Britannia one of the worst in the history of transportation. There was one death to every 17 prisoners embarked, 10 men and one woman dying out of 144 men and 44 women; but the convicts were brutally mistreated and the survivors were landed in a wretched and emaciated state. The Britannia's master, Thomas Dennott, was a sadist who, in consequence, as Governor Hunter declared,.' of some conjecture of mutiny', kept the prisoners confined in irons and flogged them unmercifully. Even the women received three or four dozen cuts from a cane for the most trivial offences......
Arrival at Port Jackson
After a voyage of 169 days, they arrived in Port Jackson on the 27 May 1797. One hundred and thirty-four male convicts and forty-three female emaciated and brutalized convicts were landed at Port Jackson.
An enquiry into the conduct of Captain Dennott was held in Sydney and is recorded in the Historical Records of Australia Series 1, Volume11.
Some of those interviewed or mentioned at the enquiry included:
Thomas Dennott - Master
Augustus Jacob Beyer - Surgeon
John Burke - convict
Lawrence Dromed (Drennan)- convict
Patrick Garnley (?Gormley)- convict (flogged) - died the following day
James Thomas Ricketts - Chief Mate
Lieutenant William Burn of the New South Wales Corps
Two men by the name of Konnas or Kennedy or Kelly- convicts (flogged)
John Kenney - convict
Isaac Froome - 3rd Mate
William Tremble (Trimble) - convict (flogged)
James Horse - convict (flogged)
James Brannon (Brennan) - convict (flogged) - died a few hours later
Rose Riley (?Hall) - convict (beaten with a stick by Dr. Beyer)
William Wharton - 2nd Mate
Grey - (Edward and George) convicts (flogged)
Richard Stapleton - convict (flogged)
John Johnson - boatswain
Strachan - soldier/flogger
Jenny Blake - convict (Gagged and hair cut off, beaten with a cane over her back, shoulders and face and afterwards placed in irons with both legs and chaining her with a chain)
Mary Fane - convict (confined in a neck yoke for two hours)
Mary Coggar (Cogan) - convict (suicide)
Francis Cox - convict (flogged for mutiny)
John Rutlidge - convict (flogged for mutiny)
James Brady - convict (flogged for mutiny)
Bryan Egan - convict (acted as cook at Rio)
John Brown - convict (flogged)
James Sandford - elderly man, dressed prisoners wounds
Mary Bryan - convict (miscarriage)- (*years later in 1817 Mary Bryan declared herself to have come free)
Peg (Margaret) Leary - convict
Henry James Purcell - private soldier of NSW Corps
Thomas Mancell - private soldier (died)
Thomas Franklin - corporal NSW Corps
(Many of the ships used in the convict trade were afterwards used for whaling or chartered for a return voyage from China by the British East India Co)
Notes and Links
1. The State Library of NSW hold the following journal of the voyage of the Britannia.....A Journal, of the proceedings of the ship, Britannia from the Downs, to Port Jackson and, China, 3 September 1796 - 30 June 1798......The name 'Massey' has been inserted over the erasure 'Gilbert' in the entry for 24 March 1797. John Gilbert is recorded as Ships Steward in the entry for 12 December 1797, and his evidence before the court of enquiry is published in the Historical Records. The log-book is written in several hands. It has 'Masseys Journal Book 1796' in ink on the front cover.
3. Information at UK National Archives about the Britannia - Extra ship, measured 1786, 2 decks, 3in bottom, length 97ft 10in, keel 77ft 3in, breadth 27ft 3in, hold 12ft, wing transom 17ft, between decks 5ft 11in, 305 tons. Voyages: (1) From Bengal 1786. Capt Thomas Dennett. Calcutta 28 Nov 1785 - Diamond Harbour 4 Jan 1786 - 2 Mar Cape - 23 Mar St Helena - 15 May Plymouth - 8 Jun Deptford. (2) From China 1798. Capt Thomas Dennett. Macao 16 Oct 1797 - 2 Dec Whampoa - Macao 28 Mar 1798 - 25 Jul False Bay - 8 Sep Cape - 17 Nov St Helena - 4 Feb 1799 Downs.
4. Jane Maher was tried in Dublin in 1796 and sentenced to 7 years transportation. In 1802 a letter was directed to the late under Gaoler of the New Prison in Dublin (Simpson) from Botany Bay.....a woman named Jane Maher, who was transported from hence, about six years ago. The subject of it is a request for an enquiry to be made after a male child she left in Dublin behind her, stating that having by her industry in the baking business acquired a property she is enable to provide for the child and wishes to have it educated, and brought up in a decent manner, and for which she will remit money. - Belfast Newsletter 2 April 1802