The use of an invasive strategy for the management of NSTEMI according to estimated risk of 6 month mortality is recommended by international guidelines. NSTEMI appropriate for coronary angiography (and percutaneous intervention) have better outcomes compare with NSTEMI who are medically managed. Whilst the national and international guidelines recommend that the timing of (in-hospital) coronary angiography (<24, 24-72, 72-96 and <96 hours) is based upon estimated clinical risk (using the GRACE risk score) there is scientific and clinical uncertainty as to the incremental benefit that more urgent invasive treatments strategies have over and above that of delayed strategies. Moreover, the investigators recent research has shown that in the UK, may NSTEMI (eligible) for coronary angiography fail to achieve care according to the recommended time thresholds, and this is associated with potentially avoidable premature death.