Henry took refuge in the Priory of St Pancras, and Gilbert accepted the surrender of the Earl of Cornwall, who had hidden in a windmill.

At the end of 1268 he refused to obey the King's summons to attend parliament, alleging that, owing to the constant inroads of Llewelyn the Last, his Welsh estates needed his presence for their defence.

At the death of Henry III, 16 November 1272, the Earl took the lead in swearing fealty to Edward I, who was then in Sicily on his return from the Crusade.

The next day, with the Archbishop of York, he entered London and proclaimed peace to all, Christians and Jews, and for the first time, secured the acknowledgement of the right of the King's eldest son to succeed to the throne immediately.

Following this defeat, Clare was relieved of his position as the southern commander and was replaced by William de Valence, 1st Earl of Pembroke (whose son had died during the battle).

They were released almost immediately and both of their lands were completely restored to them—however, they had both been taught a very public lesson and their prestige diminished and the King's authority shown for all.

Disputed hunting rights on these led to several armed conflicts with Humphrey de Bohun, 3rd Earl of Hereford, that Edward resolved.

[10] Gilbert made gifts to the Priory, and also had a "great conflict" about hunting rights and a ditch that he dug, with Thomas de Cantilupe, Bishop of Hereford, that was settled by costly litigation.

In September, he signed the Barons' letter to the Pope, and on 2 November, surrendered to the King his claim to the advowson of the Bishopric of Llandaff.

He died at Monmouth Castle on 7 December 1295, and was buried at Tewkesbury Abbey, on the left side of his grandfather Gilbert de Clare.