There was always the chance, however, that Soult might turn against the Alemtejo after all, and that Masséna might make a desperate effort to cross the Tagus and join him. Hence Wellington spent much thought in devising means to prevent this danger from coming into being. Beresford received elaborate orders as to the conduct that he was to pursue, with his corps south of the Tagus, in case Masséna attempted a passage, or Soult appeared before Elvas. In the latter case the French would be fought by an army composed of Mendizabal’s Estremadurans, Beresford’s corps, and the brigade of Portuguese line troops in Elvas, a mass of over 30,000 men. This force ought to suffice, but if the worst came, and a defeat were suffered, the army south of the Tagus would try to defend first the passages of the Zatas river (or the Benevente river as Wellington usually calls it), then those of the Almansor, and lastly the line across the neck of the Setubal peninsula, opposite Lisbon, where there was a short front of ten miles from Setubal itself (which was fortified) past the castle of Palmella to Moita on the Tagus estuary. But behind this again was the strongest defensive position of all, a Lines of Torres Vedras on a small scale[104]. The works erected here were an afterthought: they had formed no part of the original scheme for the fortification of Lisbon, but when it had been proved to Wellington that batteries on the Heights of Almada, beyond the broad Tagus mouth, might incommode the shipping in the harbour, and possibly the town itself [the range was 2,300 yards], he had ordered, early in December, that the Portuguese labourers set free from work on the old lines by Masséna’s departure should be transferred to the Almada front[105]. Here a line of 8,000 yards from sea to sea was marked out, and strengthened with no less than seventeen closed redoubts, connected by a covered way. Eighty-six guns were allotted to them, and their defence was to be given over to the marines of the fleet, and the local militia and trained Ordenança (_Atiradores nacionaes_) of Lisbon. It was calculated that Beresford would find a garrison of 7,500 men already placed in these forts if he were ever forced back on to them. It seemed impossible that such a short front, so strongly held, could ever be broken through. [104] All this may be found in Wellington’s dispatch of January 12, 1811, where he details the successive positions which Beresford must try to hold. [105] For a description of this front see Jones, _Lines of Torres Vedras_, pp. 43-5.