there is now statutory duty to report stated deaths to a coroner (Guidance for registered medical practitioners on the Notification of Deaths Regulations 2019 (1)) - see linked item
reporting to the coroner - you should indicate whether you have reported the death to the coroner by ringing option 4 on the front of the certificate and initial box A on the back. You should report to the coroner any death that you cannot readily certify as being due to natural causes
a death should be notified to the coroner as in the linked guidance below (1) - this provides detailed guidance. The broad categories for notification to the coroner are:
Circumstances in which a notification should be made under regulation 3
The death was due to poisoning including by an otherwise benign substance
The death was due to exposure to, or contact with a toxic substance
The death was due to the use of a medicinal product, the use of a controlled drug or psychoactive substance
The death was due to violence, trauma or injury
The death was due to self-harm
The death was due to neglect, including self-neglect
The death was due to a person undergoing any treatment or procedure of a medical or similar nature
The death was due to an injury or disease attributable to any employment held by the person during the person's lifetime
The person's death was unnatural but does not fall within any of the above circumstances
a death is typically considered to be unnatural if it has not resulted entirely from a naturally occurring disease process running its natural course, where nothing else is implicated. For example, this category includes scenarios in which the deceased may have contracted a disease (e.g., mesothelioma) as a result of washing his/her partner's overalls which were covered in asbestos however long before the death occurred.
The cause of death is unknown
The registered medical practitioner suspects that the person died while in custody or otherwise in state detention
The attending medical practitioner is not available within a reasonable time of the person's death to sign the certificate of cause of death
If there is an attending medical practitioner who is responsible for signing the Medical Certificate of Cause of Death (MCCD), but this medical practitioner is unable to sign this certificate within a reasonable period, then the death must be notified to the coroner.
It is ultimately for the discretion of a medical practitioner to determine what would be a 'reasonable time' based on the individual circumstances of the case. However, it is recommended that where there is an attending medical practitioner, they should be completing an MCCD as soon as possible.
It should be noted that a death must legally be registered within 5 days from the date of death, and that the MCCD is needed for such a registration to be made within this time limit. Therefore, the completion of the MCCD must not exceed this time limit.
The identity of the deceased person is unknown
Ministry of Justice. Guidance for registered medical practitioners on the Notification of Deaths Regulations 2019
Manchester City Council (2007). Death Certification Guidance for doctors certifying cause of death.