ISLAMABAD: Former chief justice of Pakistan Iftikhar Muhammad Chaudhry on Saturday said an interim prime minster should be appointed during Prime Minister Nawaz Sharif’s absence. Warning of a “constitutional crisis” if such a move is not made, Chaudhry – who is also the chief of the Pakistan Justice and Democratic Party – said, “No one can perform the duties of the prime minster in his absence.” He went on to say that without approval of the prime minister, it was constitutionally impossible to finalise the budget since the rules of business clearly state “only the PM can approve and sign it”. The development comes after Nawaz Sharif, who is in London for medical treatment, will undergo an open-heart surgery on Tuesday and will likely remain hospitalised for at least a week.