Hopes of peace and reconciliation raised by the loveday proved superficial and short-lived. Although at first the Yorkists appear to have been treated fairly, the duke of York received no particular favor from King Henry, and the earl of Warwick proved to be a lightning rod for trouble. He remained captain of Calais, and he continued to commit acts of piracy in the Channel, which embarrassed the government. In autumn 1458, while Warwick was in England for a council meeting, some of his men – and perhaps the earl himself – engaged in a ‘vulgar brawl’ with men of the royal household. Warwick returned to Calais, from where he declared that he would never give up his captaincy. The political situation deteriorated. Matters came to a head in October 1459 in an armed confrontation between the Yorkists and the king outside the town of Ludlow. Faced with a superior royalist force and desertions within their own ranks, the Yorkist leaders fled: the duke of York to Ireland, and the earls of Warwick, Salisbury and March to Calais. A parliament held at Coventry attainted them in November, making further confrontation certain as they plotted their return. From Calais, the earls launched a propaganda campaign to raise public sympathy for their cause. As in the past, they swore that they were loyal to Henry VI and meant himno harm; their quarrel was with the malicious persons about him who had wronged them. They were coming to rescue the realm. The resulting invasion in June 1460 was a stunning success. Having gained entry to London on the basis of their sworn intentions and the threat of violence from their armed followers, Warwick and March continued north with an army to confront the king.

The battle of Northampton (10 July 1460) was devastating for the Lancastrians: among King Henry's supporters the duke of Buckingham, the earl of Shrewsbury, Viscount Beaumont and Thomas Percy, Lord Egremont, were killed; Henry himself was taken prisoner. Although Warwick, Salisbury and March swore fealty to him, few onlookers doubted that power had irrevocably changed hands. The victors could not realistically be expected to submit themselves again to Henry's will. Warwick became the dominant personality. He replaced the government's officers and Henry's household personnel with men loyal to him.