Battle of Brentford ( 1642 ) The Battle of Brentford was a small pitched battle which took place on 12 November 1642 , between a detachment of the Royalist army , ( predominantly horse with one regiment of Welsh foot ) under the command of Prince Rupert and two infantry regiments of Parliamentarians with some horse in support . The result was a victory for the Royalists . Background . After the Battle of Edgehill ( 23 October ) King Charles I captured Banbury ( 27 October ) and was greeted by cheering crowds as he arrived in Oxford on 29 October . Prince Rupert swept down the Thames Valley , capturing Abingdon , Aylesbury and Maidenhead , from where he attempted to capture Windsor though failed due to Parliamentary strength there . After this many officers wanted to open peace negotiations , contrary to Rupert ' s desire to carry on to London , but the king agreed with the officers and so the Earl of Essex managed to overtake them and reach London with his Parliamentary army by 8 November . Prelude . While in Reading Charles decided that the peace talks were inconclusive , and that if he advanced on London it might place him in a better negotiating position . So on 11 November he moved his army closer to London by encamping at Colnbrook and to put further pressure on the Parliamentarians he ordered Prince Rupert to take Brentford . On reaching London the Earl of Essex had not been idle , and had positioned men on the western approaches to London . One force covered the bridge at Kingston upon Thames while another , to the west , barricaded the small town of Brentford which lay on either side of the Thames concentrating their efforts in the proximity of the bridge that connected Old Brentford to New Brentford . Battle . On 12 November under cover of an early morning mist Rupert ' s cavalry and dragoons attacked the two regiments of Parliamentary foot , one under the command of Denzil Holles and the other of Lord Brooke , which were barricaded inside Brentford . The initial attack by the cavaliers on Sir Richard Wynne ' s house , an outpost west of Brentford held by Holles ' s regiment , was repulsed . So a Welsh regiment of foot were ordered into action by Rupert . The combined force successfully captured the outpost and carried forward their attack into Brentford itself . They drove Holles ' s men over the bridge into the defences manned by Lord Brooke ' s men . These in turn were driven out of the town into open fields . The fighting continued into late afternoon , before the survivors of Holles ' s and Brooke ' s regiments were able to disengage under the protection of John Hampden ' s infantry brigade , which arrived from Uxbridge to cover their withdrawal . Nevertheless a large number of Holles ' s men were drowned while trying to escape their pursuers by swimming across the Thames . The Royalists captured 15 guns and 11 colours and about 500 prisoners , including John Lilburne who was a captain in Brooke ' s regiment . Aftermath . Having won the battle the Royalist forces sacked the town . This action encouraged those Londoners who feared for their property to side with the Parliamentarians . On 13 November the main Parliamentary army under the command of Earl of Essex ' s heavily reinforced with the London trainband s and other London citizenry , assemble as an army of about 24 , 000 on Chelsea Field and advanced to Turnham Green in the vicinity of the main body of the Royalist army . At a standoff known as the Battle of Turnham Green , the senior Parliamentarian Officers not trusting the training of the their forces in a battle of manoeuvre chose not to attack , and the King decided not to press his advance on London by giving battle against a force much larger than his decided , as it was near the end of the campaigning season , to retreat to Oxford where his army could be billeted over the winter . Lilburne was the first prominent Roundhead captured in the war , the Royalists intended to try him for high treason . But when Parliament threatened to execute Royalist prisoners in reprisal , Lilburne was exchanged for a Royalist officer ( see the Declaration of Lex Talionis ) . Keith Roberts and John Tincey cite several Parliamentary propaganda pieces which include accusations of atrocities . One included accusations that the Cavaliers used Roundhead prisoners of war ( captured at Keynote ) , as human shields — Their cloths were shot full of holes but all of the survived unharmed . They also note that in another publication of about the same period that Cavalier camp followers were accused of murdering wounded Roundhead soldiers . They argue that " The wide circulation of exaggerated accounts of these events helps to explain the growing antipathy of Parliamentarian soldiers to their Royalist opponents and helps to explain the mutilation of Royalist camp followers after the Battle of Naseby " .