However, the Arab Movement lived on Allenby’s good pleasure, so it was needful to undertake some operation, less than a general revolt, in the enemy rear: an operation which could be achieved by a raiding party without involving the settled peoples; and yet one which would please him by being of material help to the British pursuit of the enemy. These conditions and qualifications pointed, upon consideration, to an attempted cutting of one of the great bridges in the Yarmuk Valley.
It was by the narrow and precipitous gorge of the River Yarmuk that the railway from Palestine climbed to Hauran, on its way to Damascus. The depth of the Jordan depression, and the abruptness of the eastern plateau-face made this section of the line most difficult to build. The engineers had to lay it in the very course of the winding river valley: and to gain its development the line had to cross and recross the stream continually by a series of bridges, the farthest west and the farthest east of which were hardest to replace.
To cut either of these bridges would isolate the Turkish army in Palestine, for one fortnight, from its base in Damascus, and destroy its power of escaping from Allenby’s advance. To reach the Yarmuk we should need to ride from Akaba, by way of Azrak, some four hundred and twenty miles. The Turks thought the danger from us so remote that they guarded the bridges insufficiently.
Accordingly we suggested the scheme to Allenby, who asked that it be done on November the fifth, or one of the three following days. If it succeeded, and the weather held up afterwards for a fortnight, the odds were that no coherent unit of von Kress’s army would survive its retreat to Damascus. The Arabs would then have their opportunity to carry their wave forward into the great capital, taking up at the halfway point