GPs Drs Hoghton & Chadwick have produced a bioethical mnemonic ‘CURB BADLIP’, for all healthcare professionals in England, Scotland, and Wales for use in patients aged 18 or over in an emergency:

C—communicate. Can the person communicate his or her decision?
U—understand. Can the person understand the information being given?
R—retain. Can the person retain the information given?
B—balance. Can the person balance, or use, the information?
B—best interest. If there is no capacity can you make a best interest decision?
AD—advanced decision. Is there an advanced decision to refuse treatment?
L—lasting power of attorney. Has lasting power of attorney been appointed?
I—independent mental capacity advocate. Is the person without anyone who can be consulted about best interest? In an emergency involve an independent mental capacity advocate
P—proxy. Are there any unresolved conflicts? Consider involving the local ethics committee or the court of protection appointed deputy.

Assessing patient capacity: Remember CURB BADLIP in the UK
BMJ 2010 340: c1285