The ‘convention in place’ is a relatively straightforward one — when the current/incumbent CJI retires (all Supreme Court judges retire at the age of 65) the senior-most judge of the apex court among those remaining becomes the CJI.

This is not a question of age, but depends on when a judge was appointed to serve on the Supreme Court. The longer a judge has been part of the Supreme Court, the more senior he or she is.

To illustrate this, imagine that when the next CJI is set to retire, there are two judges – one who is 63 and has been a judge of the apex court for five years; and one who is 62, but has been at the court for six years. Following the seniority convention, the judge who is 62 will be considered the more ‘senior’, and should become the next CJI.

To illustrate this, imagine that when the next CJI is set to retire, there are two judges – one who is 63 and has been a judge of the apex court for five years; and one who is 62, but has been at the court for six years. Following the seniority convention, the judge who is 62 will be considered the more ‘senior’, and should become the next CJI.

Things can get interesting when two judges are appointed to the Supreme Court on the very same day, as often happens. CJI Dipak Misra, for instance, was sworn-in on the same day as Justice Chelameswar (10 October 2011), and despite being four months younger, Justice Misra became CJI in August 2017.

Justice Ray was fourth in terms of seniority when CJI SM Sikri retired on 25 April 1973, behind Justice JM Shelat, KS Hegde and AN Grover, despite which he was appointed as the next CJI.

When CJI Ray retired on 28 January 1977, the senior-most judge as per convention was Justice HR Khanna. Justice Khanna, however, was not loved by Indira Gandhi’s government, having courageously authored the minority judgment in the ADM Jabalpur case.