Warwick posted himself at the mouth of the Thames, to prevent any advance towards London, or any relief to Colchester; but he did not deem himself strong enough till he should be joined by another fleet under Sir George Ayscough, from Portsmouth. With this arrival Warwick was in a condition to attack the prince's fleet, but he lay still, nor did the prince appear more inclined to assail him. He was satisfied to intercept merchantmen coming into port, and then demand their ransom from the City. This occasioned a brisk correspondence between London and the prince, under cover of which proposals were made by the prince and his counsellors for the City opening its gates and declaring for the king. But the demand of the prince for ten thousand pounds as ransom of the merchant ships disgusted the City, and presently after came the news of the total defeat of the Scottish army at Preston. On this the prince sailed away again to Helvoetsluys, without attempting anything more. His fleet, according to Clarendon, like the Court and army of his father, was rusted with factions, and so incapable of any decided course of action. But the Earl of Warwick did not present a more flattering aspect. Though it is confessed that he was amply strong enough after Ayscough's junction to have beaten the prince, he satisfied himself with watching him off, and followed him at a respectful distance to the Dutch coast. He is said there to have persuaded the disappointed sailors to return to the service of the Parliament, and thus recovered most of the ships. But the public was greatly dissatisfied with his conduct, and the Independents did not hesitate to declare that they were always betrayed by the cowardice or disaffection of noble commanders. The whole war bore striking evidences of this fact; and Clarendon asserts that Warwick had an understanding with his brother Holland, and would almost certainly have gone over had the Scottish invasion succeeded. Clarendon declares that the Parliament of Scotland had sent Lord Lauderdale to the Hague, to invite Prince Charles to go to Scotland and put himself at the head of affairs there for his father, in order to encourage the endeavour to put down the Independents, who were at once hostile to the king and the Solemn League and Covenant; but that the news of the defeat of Hamilton defeated that object. By the end of August all the attempts of the Royalists were crushed.