Despite his poor results in France he remained highly regarded by his uncle King Edward I, who treated him almost as a son. After his return to England John became involved in the Scottish Wars. He was probably at the Battle of Falkirk in 1298. He was certainly at the Siege of Caerlaverock in 1300. The nobles who joined Edward I at the Siege of Caerlaverock, including John of Brittany, were commemorated in the Roll of Caerlaverock which named each noble and described their banner. In this roll, the banner and description of John of Brittany immediately follows that of his uncle King Edward I.