A tension pneumothorax is an important reversible cause of deterioration in the multiply-injured patient, but it is not always easy to make the diagnosis. Features that indicate the development of a tension pneumothorax can be subtle in the spontaneously breathing patient. The ‘classical’ features may not all be present and in addition, the clinical signs of tension may develop over time with increasing patient compromise. This is a life-threatening situation, which requires relief in order to save the patient's life. A tension pneumothorax can be managed in one of three ways: needle decompression, insertion of an intercostal chest drain or by open thoracostomy. Needle decompression can be performed quickly and safely by paramedic crews using well-established techniques in both the conscious and unconscious patient. We describe a case of a 55-year-old male who was ejected from his motorcycle at high speed. He was conscious with a Glasgow Coma Score (GCS) of 15 and complaining of difficulty breathing. In contrast to the often quoted classical features of a tension pneumothorax, we review the more common clinical findings in tension pneumothoraces as illustrated in this case study. We aim to show that the diagnosis can be reached by careful history taking, examination, and attention to patient physiology. The case study also shows that a tension pneumothorax can be a dynamic developing situation in which patient compromise develops over time. We highlight that much can be done in the pre-hospital phase to treat such a patient while expediting transfer to hospital. We review the pre-hospital management of a tension pneumothorax and also describe our procedure for pre-hospital chest drain insertion in the context of effective teamwork between a paramedic road crew and an attending helicopter emergency medical service (HEMS).