Early in 1347 Edward took steps to substantially increase the size of his army; in large part he was able to do this because the Scottish army's threat to the north of England and the French navy's threat to the south were much reduced. It is known, for example, that he ordered the recruitment of 7,200 archers; this is nearly as many men as the entire invasion force of the previous year. In late April the English established a fortification on the end of the spit of sand to the north of Calais, which enabled them to command the entrance to the harbour and prevent any further supplies reaching the garrison. In May, June and July the French attempted to force convoys through, unsuccessfully. On 25 June the commander of the Calais garrison wrote to Philip stating that their food was exhausted and suggesting that they may have to resort to cannibalism. Despite increasing financial difficulties, the English steadily reinforced their army through 1347, reaching a peak strength of 32,000; the largest English army to be deployed overseas prior to 1600. 20,000 Flemings were gathered within a day's march of Calais. English shipping ran an effective ferry service to the siege from June 1347, bringing in supplies, equipment and reinforcements.