A man who was discharged too quickly from hospital after suffering serious head injuries in a street attack has won a six-figure compensation package to cover the cost of the lifetime of care and support he will need.

The man, aged in his 40s, was admitted to a hospital accident and emergency department after he had been treated for wounds to his head by paramedics at the scene of the violent incident. He was sent home three hours later – only to be discovered by his partner the next morning in a deeply unconscious state.

Despite urgent readmission and surgery, he has been left with permanent brain damage, seriously affecting his mobility, memory and ability to concentrate to the extent that he will never be capable of leading a fully independent life.

The NHS trust which managed the hospital admitted that there had been a negligent failure to keep him longer in hospital. However, it argued that the bulk of the damage he suffered had been inflicted in the initial assault and that earlier medical treatment would have made little or no difference to the outcome.

The man's lawyers negotiated a compromise by which he will receive a lump sum of £200,000, plus index-linked and tax-free annual payments of £23,500 for life.