[3] Being a minor aged 15 at his father's death, he became a ward of Nicholas Seagrave until 1293, when he recovered livery of his estates.
[3] By 1295, Ferrers was abroad on royal service, and acting as Edward I's agent at the Duke of Brabant's court in Hainault.
Although he was short of money at the time (having had to mortgage the Newbottle manor for £200), this did not prevent him taking part in the King's military campaign.
In 1301 William Ferrers was signatory to the (eventually unsent) Barons' Letter of 1301 to Pope Boniface VIII, in which Ferrers and 95 other English barons and five English earls repudiated the Pope's claim to overlordship of the Kingdom of Scotland and defended the aggressive policy of King Edward I.
[7] Financial problems in the early fourteenth-century led him into conflict with his cousin John Ferrers which centred over a disputed claim to the Newbottle manor.