In September a truce was agreed and much of the English army left the border area to join King Edward III's campaign in France.

[3] The disastrous English Weardale campaign brought Isabella of France and Roger Mortimer, regents of the newly-crowned 14-year-old King Edward III (r. 1327–1377), to the negotiating table.

[14] Berwick, on the North Sea coast of Britain, is on the Anglo-Scottish border, astride the main invasion and trade route in either direction.

[15] According to William Edington, a bishop and chancellor of England, Berwick was "so populous and of such commercial importance that it might rightly be called another Alexandria, whose riches were the sea and the water its walls".

[16] Prior to its capture in 1333 it was the most successful trading town in Scotland, and the duty on wool which passed through it for export was the Scottish Crown's largest single source of income.

A large part of the English force subsequently moved south to join Edward's planned campaign in northern France.

[27] Many members of the garrisons of the English border fortresses left their posts without permission to join Edward's expedition to France.

The Constable of Norham Castle, an important English border fortification, attempted to counter attack with part of his garrison and some locals, but this scratch force was routed.

He continued with his campaign in France,[29] where he led a chevauchée – a large-scale mounted raid – across Picardy, attempting to draw the French army into battle.

After training for six days they attacked Berwick town on 6 November, landing under the cover of night and escalading the walls shortly before dawn.

The Guardian of Scotland, Robert Stewart, who was acting as regent for the imprisoned David II, took personal control of the siege of the castle.

[33] According to other accounts it was not until he disembarked in England with the army on 12 November, after the negotiations with the French had failed, that he learnt of the fall of Berwick.

[19][23] In any event, Edward was in Newcastle in the north by Christmas Eve (24 December), where a large army was assembling, and a small fleet was being prepared to supply it.

[35] The English laid siege to the town and the Scots could expect no relief force, according to a contemporary "by reason of the discord of the magnates".

At some stage the French men-at-arms under Garencières had withdrawn to France; they had collectively brought Scotland back into the war and individually enriched themselves with loot from Berwick.

The Scots offered to parley[36] and not wishing to be delayed Edward agreed to let them leave, even allowing them to take what plunder they could carry.

[41] Clifford Rogers also believes that Edward intended to march on Perth, supplied from the sea by the large fleet he had assembled.

The English were severely harassed en route and arrived in England at the end of February with the army in poor condition.