The ambassadors of Austria, Prussia, and Russia opposed the granting of a new constitution, and Dom Miguel still maintained a threatening attitude. Palmella accordingly applied to Great Britain for troops to support his government. This request created no little difficulty. It was impossible for Great Britain to allow the government of Portugal to fall into the hands of a party resting for support on the absolutists in Spain and the French army, and it was equally impossible to employ British troops to maintain the cause of the King of Portugal against his ultra-royalist subjects when Great Britain had protested so vigorously against the kings of Spain and the Two Sicilies receiving foreign assistance against their liberal subjects; there were moreover no troops that could well be spared. Canning accordingly contented himself with despatching a naval squadron to the Tagus to act as a moral support to the king. As the event proved, this squadron was sufficient to determine the course of events. At the same time Canning refused to guarantee any constitution, though when France joined the eastern powers in threatening the proposed constitution, he intimated his readiness to resist by force of arms any foreign intervention in Portugal. On April 30, 1824, Dom Miguel attempted another _coup d'état_, and was for nine days in possession of Lisbon, where he made wholesale arrests of his political opponents. John VI. was, however, supported by all the foreign ambassadors, and on March 9, by their advice, he went on board the British ship of war, _Windsor Castle_, where he summoned his son to appear before him. Dom Miguel thought it wisest to obey; the king sent him abroad, and the attempt at a revolution was over for the present. The junta appointed in the previous year to frame a constitution now reported in favour of a revival of the ancient cortes, and this proposal was accepted by the king. The cortes were not, however, actually assembled; still, the mere fact of Dom Miguel's absence left the government a little stronger.