Whilst Sir George Ayscue was bringing the colonial settlements to obedience of the Parliament, the work of utterly extirpating the king's authority had been completed at home. Blake had returned from the Mediterranean in February, leaving Penn to take his place. He was well received by the Council of State, and rewarded not only by thanks, but by a grant of money. The Government had immediate need of his services again. Though completely beaten in England, the Royalists were still struggling in Scotland, and they held possession both of the Scilly and the Channel Isles. From these posts they carried on harassing privateering war against commerce. It was not only the damage they did to trade which made these garrisons highly inconvenient to the Government. They had not been very careful to distinguish between English and foreign property in their captures, and had at least done enough to justify the Dutch in threatening to take the law into their own hands. The fear that Tromp, who commanded the naval forces of the States in the Channel, would seize at least upon Scilly was avowed, and was possibly not wholly unfounded. The most effectual way to put a stop to any enterprise of the kind was manifestly to eject the Royalist garrisons from these posts. In April Blake convoyed a military force sent to take possession of the Scilly Isles. The service was rapidly and effectively performed, with the help of Ayscue, who was starting on his voyage to America, and of Colonel Clarke, a military officer despatched by Desborow. Sir John Grenville, the Royalist governor, held out until the 24th of May, and then brought a resistance, doomed to be unavailing, to an end by surrender. The operations against the Channel Isles were suspended for a short time by the march of the Scots army under Charles II. into England. But after the "crowning mercy" of Worcester in September they were resumed. On this occasion Blake had the sole naval command, and his military colleague was Colonel Hayne. Sir George Carteret was helped to prolong his defence by the bad weather, which made it impossible to land the troops for days. But the end was inevitable. With an overwhelming naval force at their command, and the now completely victorious New Model Army to draw on for reinforcements, it was at best a mere question of time when the Parliament would obtain possession of the islands. So soon as he had done enough for honour, Sir George Carteret saved his estate from confiscation by surrendering his forts. In these operations the share of the navy had in a sense been subordinate. It had comparatively little to do with the fighting, and its work had been almost wholly confined to carrying the troops over and landing them. But in another sense these last Royalist garrisons were in reality taken by the navy. If it had not acquired such a commanding superiority of strength at sea as destroyed every Royalist hope of help, Grenville and Carteret might have held out for long. In this, as in the earlier stages of the war with the king, it was the possession of the navy by his enemies which proved ruinous to him.