The Dublin Parliament in 1782 had declared its independence of English jurisdiction, and the air of its Court in College Green was charged with Irish spirit. When the Writ of Error had been argued for a day, one of the legal peers, Lord Pery, showed his mettle by suggesting that the Londoners’ Charter was defective for lack of the Irish Great Seal. This was a deadly thrust; but he then aimed a home blow at their opponent. He suggested that, although Charles II. made the grant to Lord Donegall earlier than the Charter, the Londoners retained priority under their original Charter from James I., because the annulment of the latter took place under an English decree of Charles I., which did not extend to Ireland. Therefore, he contended, they still possessed their ancient rights intact. These objections raised the slumbering wraith of international conflict with Great Britain at an embarrassing moment. They bristled with delicate political problems, and the Lord Chancellor cleverly foiled them.

Dealing first with the Donegall Patent, he narrated that he had acted as counsel for the Londoners at the trial at Armagh in 1788, and had gone there “for the very purpose of showing that Lord Donegall had no title—but a clause in the Act of Settlement put that out of the case.” Turning to the Charter, he declared that the Londoners held by possession for over a century; and, although the Great Seal of Ireland might originally have been necessary to it, a good possessory title had been acquired by the lapse of years. These statements appeared conclusive.

Yet the Act of Settlement had no operation to legalise a Patent such as Lord Donegall’s. The Chancellor was entirely mistaken on this point. As to the Charter, the lack of the Great Seal was felt to be so serious that a Bill was rushed through Parliament a few weeks later to mend the flaw. Both of Lord Pery’s objections, therefore, struck at the marrow of the case; and the Chancellor’s way of meeting them showed that he was sapping for a channel of escape from the political perplexities they presented. Perhaps, too, he sought to screen his blunder at Armagh in failing to raise the question of Lord Donegall’s title, for the Act of Settlement offered no obstacle to his doing so. It merely legalized Patents of property vested in the Crown, which had been confiscated because of the Rebellion of 1641. The “special verdict” indicated (wrongly) that it was by virtue of a confiscation then made that the Crown obtained the fisheries, whereas such title as it possessed (if any) was enjoyed previously.

Equally erroneously the “special verdict” alleged that the fisheries were sequestered by Cromwell. They were given away by Cromwell, but had not been seized by him. Only Patents to property seized in consequence of the Rebellion were “ratified and confirmed” by the Act of Settlement, and Lord Donegall’s grant was not in that category. The fisheries were given up by his ancestor a year before 1641, and were, therefore, not “sequestered” owing to the Rebellion. The Lord Chancellor, unaware of this, allowed the special verdict to be misframed at Armagh, and then misapplied the law on the Woolsack. His pronouncement that the Act of Settlement “confirmed” the Donegall grant, coming from one who had been retained as counsel to oppose it, silenced Lord Pery.

These high clashes between the Law Lords almost caused the fate of the “traps” to be lost sight of, and probably helped to bring about the rejection of the Londoners’ appeal. The House held unanimously in favour of Lord Donegall, whose victory was the sweeter because it had been won without provoking any challenge to the validity of his Patent. His well-judged tactics won for it the sanctity of a legal baptism. Soon afterwards he applied in Chancery for an order to prostrate the traps. The Londoners fought on; and, under the intricate procedure of that epoch, brought the matter from Court to Court.

In 1801, after the Dublin Legislature had been abolished by the Act of Union, a fresh appeal reached the Lord Chancellor. He delightedly entertained it, and for the third time heard a case in which he had been counsel for the appellants. The Irish House of Lords was no more, and, sitting alone, he learnedly decided in favour of the Londoners. Lord Donegall was not only beaten, but condemned in costs, and the traps were saved. Safe though they were, his Patent was still safer, for its validity had never once been called in question in any Court, and the legal struggle was confined to the right to erect the traps in a part of the river to which he laid no claim.

Thus ended a thirty years’ litigation. The plaintiff never stirred more. The Londoners, grateful for their escape and for the Act which dispensed with the Great Seal to their Charter, were content to enjoy the tidal fishings with the traps, unmolested. Accepting the view of their trusty Lord Chancellor, that Lord Donegall’s Patent had received confirmation by the Act of Settlement, they silently abandoned their rights in the non-tidal Bann.

Taking courage at this, Lord Donegall began to make lettings of the river. He first gave his brother-in-law (and agent), the Reverend Edward May, a lease of the Bann in 1803 for 61 years at £50 a year of the salmon “within the known and accustomed limits of the fishery.”

In 1805 this lease was registered publicly, and as no one challenged the letting, the Reverend Edward May assigned it in 1811 for £500 to Sir George Hill, Recorder of Derry, who was also a lessee of the Londoners’ fishery in the tideway. Other persons then consented to pay rent for the river to Lord Donegall, in the belief that the litigation of 1769-1788-1795-1801 had made the Bann his. In 1827 Lord O’Neill accepted from him a lease of the eel-fisheries of the river at £369 a year, paying the enormous fine of £7,384.

Thus in the first half of the nineteenth century the Donegall interest formidably entrenched itself behind the Patent. There was, however, no attempt to exclude the public from Lough Neagh until 1873, and it was then only made as a consequence of the litigation as to the Bann. For in 1868 the Londoners woke up to the fact that they were owners of “the entire Bann.” After centuries of torpor they claimed it by ejectment, as if nothing had happened since the reign of James I. While, however, they lay asleep, successive Marquises of Donegall had made themselves masters of the stream. The ejectment was met by numberless defences; and, after some legal sparring, they lost heart. In 1872 the suit ended in a settlement, whereby the “Irish Society” bought up a lease of the non-tidal salmon fishery for £2,250, and covenanted to pay a rent of £80 a year to Lord Donegall. The valuable eel-fishery of the river they left in his hands.