The Committee of Both Kingdoms, (known as the Derby House Committee from late 1647), was a committee set up during the Wars of the Three Kingdoms by the Parliamentarian faction in association with representatives from the Scottish Covenanters, after they made an alliance (the Solemn League and Covenant) in late 1643.
When the Scottish army entered England by invitation of the English Parliament in January 1644 the Parliamentary Committee of Safety was replaced by an ad hoc committee representative of both kingdoms which, by parliamentary ordinance of 16 February, was formally constituted as the Committee of Both Kingdoms. The English contingent consisted of seven peers and 14 commoners. Its object was the management of peace overtures to, or making war on, the King. It was conveniently known as the Derby House Committee from 1647, when the Scots withdrew. Its influence long reduced by the growth of the army's, it was dissolved by Parliament on 7 February 1649 (soon after the execution of Charles I on 30 January) and replaced by the Council of State.[1]
A sub-committee on Irish affairs met from 1646 to 1648. The sub-committee spent, in Ireland, money raised by the Committee of Both Houses.[1]