Yes, there are a few exceptions when treatment may be able to go ahead without the person’s consent, as it may not be possible to immediately gain the consent required, such as when a person needs emergency treatment to save their life, but they’re incapacitated. Even in this case, medical professionals are afterwards required to state their reasons as why the treatment was necessary.
Consent cannot always be sought when a patient immediately needs an additional emergency procedure during an operation. Again, there has to be a clear medical reason why it would be unsafe to wait to obtain consent.
In some cases, patients with severe mental health conditions, may lack the capacity to consent to the treatment of their mental health (under the Mental Health Act 1983).