French fleets insulated the south coast, ravaged the Isle of Wight, and took and burned Rye, Hastings, and other places. Measures for the defence of the country were imperatively needed, and parliament met on 13 Oct. The majority of the commons who were now returned consisted of the same members who had sat in the Good parliament of 1376, and De la Mare was again the speaker. On the question of means to be taken for the repulse of French invasion, a curious scene is reported. The commons demanded assistance in their consultations from a committee of twelve peers, with the Duke of Lancaster at their head. Thereupon Lancaster, rising from his seat and bending his knee to the king, proceeded to refer to the imputations which had been cast upon him by the commons, and indignantly repelling the charges he challenged his accusers to appear. Crowding round him, prelates and lords interposed to calm his anger, and to assure him that such things could not be true, and the commons vouched their request for his advice as the best proof of their trust in his integrity. On this Lancaster allowed himself to be pacified, but on the understanding that in future the inventors of such evil reports should be duly punished. His protests were not without effect in lulling the suspicions of his adversaries. Early in 1378 he succeeded in obtaining charge of the subsidy which parliament had granted to carry on the war, and a fleet was got ready. Lancaster was appointed lieutenant in France and Aquitaine on 17 June 1378, and some small successes were gained off Bayonne over some ships of the Spanish fleet which had pined the French. But he was altogether wanting in enterprise, He is accused of loitering with the fleet on the coast and of letting his men live at free quarters, and even of outraging decency by appearing in public in company with his mistress, Catharine Swynford. At length, after the western fleet had been defeated at sea by the Spaniards and the Scots had attacked the east coast, he sailed for Brittany, and sat down before St. Malo. But an assault which he delivered utterly failed, and the expedition ingloriously returned.
The unpopularity which Lancaster incurred from this want of success was further increased by an outrage perpetrated by some of his followers. Two esquires, named Haule and Shakel, had taken prisoner in the Spanish campaign the count of Denia, who had left in their hands his son as surety for payment of his ransom. Lancaster, thinking that the possession of the young count's person would aid his designs upon the Castilian throne, demanded his surrender. This was refused, and Haule and Shakel were sent prisoners to the Tower. They succeeded in escaping, and took sanctuary at Westminster, but they were pursued by Ralph de Ferrers, who, while mass was being celebrated, broke in, slew Haule, and carried Shakel back to prison, 11 Aug. 1378. Excommunication of the perpetrators of the sacrilege followed, and the Bishop of London published the sentence thrice weekly, as he preached at St. Paul's. Enraged at this, Lancaster is said to have declared in the council at Windsor that he was ready to ride to London and drag the bishop from the midst of the ribald citizens, and bring him before the court. His next step was to procure the summoning of parliament to sit at Gloucester, where it would be beyond the influence of the hostile Londoners and their bishop, 20 Oct.; and it was announced that he was meditating a renewed attack upon the church. The result, however, if he had any such intention, did not fulfil his wishes. The commons showed themselves no less steady than before in demanding redress of abuses, and in insisting on a scrutiny of the expenditure before making further grants.
The history of the next three years is one of futile military expeditions, repeated parliaments, and continued demands for supply. The parliament held at Northampton 5 Nov. 1380 granted the unpopular poll-tax which led to insurrection. Lancaster does not come personally forward during this period. On 19 Feb. 1379 he was constituted lieutenant on the marches towards Scotland, and on 12 June commander-in-chief beyond seas, an appointment which nominally gave him the directionof the expedition sent under Thomas of Woodstock, now earl of Buckingham, into Brittany. On 6 Sept. 1380 he was appointed special envoy to treat with Scotland, with a view to negotiations for a peace, and on 20 May 1381 took command of the border.
It was during Lancaster's absence in the north that Wat Tyler's insurrection broke out. The insurgents were in possession of London, and the duke's palace of the Savoy was destroyed, 13 June 1381. It is said that the rumours of the rising which reached him caused him to hasten to conclude a treaty with the Scots, 8 June. The panic spread, and the insurgents were reported to be marching north to take vengeance on Lancaster; his wife Constance hastened from Leicester, and sought a refuge at Pontefract, but the gates were closed against her, and she was compelled to journey on to Knaresborough. Lancaster himself fared no better. His old follower Northumberland, perhaps jealous of his presence in the north, refused him