The treaty failed to end concerns over attempts to alter the Utrecht settlement, illustrated by the 1721 Treaty of Madrid, a mutual defence agreement between France, Spain and Britain. The British monarch, George I, agreed to raise the question of returning Gibraltar in Parliament 'at a favourable opportunity', which the Spanish viewed as a commitment to return it. Commercial tensions between the two countries and frustration at the lack of progress would lead to a new Anglo-Spanish War in 1727.