The driver of the Ford and a passenger travelling in the same vehicle – a man and a woman both in their 60s – were pronounced dead at the scene.
Their next of kin has been informed and are being supported by specially trained officers.
Shortly afterwards, officers arrested a 20-year-old man from Berkshire on suspicion of driving with excess drugs.
He was subsequently arrested on suspicion of causing death by dangerous driving and remains in police custody at this time.
Road closures were in place while emergency services were in attendance, however both sides of the carriageway have now fully reopened.
Investigating officers would like anyone who witnessed the collision or saw the vehicles, and the manner in which they were being driven to come forward.
They’re also keen to speak to anyone who has dashcam footage of the collision.
Anyone with information should contact the force quoting incident 323 of 24 September.