One of London's specialist mental health cars helps to ease pressure on the service from the growing number of patients in crisis, including a homeless university student living rough.

As London sleeps. crews battle to care for vulnerable, lonely and critically ill patients, including an elderly man who has suffered catastrophic trauma after a fall downstairs.

Aer a frantic 999 caller reports witnessing a relative being attacked by an XL bully dog, crews are dispatched – but the dangerous dog is still on the loose.

Crews respond to a patient in traumatic cardiac arrest after being stabbed. With his life hanging in the balance, doctors have no choice but to operate on him at the roadside.

Call handler Caelainn and her colleagues are sexually harassed by a persistent caller using a withheld number, which makes it hard to block his repeated calls.

Patient Ron suddenly stops breathing whilst visiting London from the Isle of Wight. With his condition critical, a bystander intervenes to try to save his life.