Newbury 1643 is one of the decisive campaigns of the English Civil War, marking a turning point in the course of the conflict. This work shows that the battle of Newbury represented the last realistic chance for the king to win a military victory over Parliament. When on 10 August 1643, King Charles summoned the City of Gloucester to surrender, the city's only hope lay in a relief expedition from London and the Earl of Wessex was forced to send his weakened army to face the king. The two forces met at Newbury and the Londoners more than held their own against the best of the king's cavalry. After a battle both the armies withdrew in good order, the King returning to Oxford. The capital was secure, her people committed to Parliament and the King's cavalry were no longer invincible - the balance of power had shifted irretrievably.