On 1 May, 1646, the army was before Oxford, and two days later Fairfax and his officers, including Okey, made a survey of the town which they found to be strongly defended. A Council of War, at which Okey was present, decided that it was inadvisable to storm the town and the Governor was offered generous terms which, after protracted negotiations, he accepted. On 24 June the surrender took place and the garrison marched out with colours flying and drums beating. When Worcester surrendered in July its Governor, Colonel Henry Washington, signed the Articles of Surrender before Okey and Colonel Bridges. On 14 September the Earl of Essex died and on 22 October his funeral service took place with great solemnity at Westminster Abbey, Okey being among the numerous high-ranking officers who took part in the procession and thus paid their last respects to one who, although prominent in the early years of the war, had had no part in the victories of the New Model.

With the fall of Oxford the First Civil War was virtually at an end, although a few isolated garrisons held out for the King. For many months the relations of Parliament and army were to be of greater importance than military operations. Okey’s name appears but rarely in the accounts of this period of intrigues, debates, committees and petitions, and it is sufficient to trace only the main current of events, drawing attention to any particular episode in which he was implicated.

The last six months of 1646 were spent in negotiations in which the King, the Scots and the English Parliament took part. Charles, however, was bent on playing off one against the other the parties among the victors, and the negotiations were fruitless. In January 1647, he was left by the Scots in the hands of the English Commissioners—two years later he was to pay with his head for his own duplicity, but for the moment his hopes of success for his policy were not without foundation.