But patience with this exclusive club has been eroding. The complaint is that the present structure, with the P-5 and a rotating membership of 10 other countries, reflects a world view based more on who won the Second World War than on present-day realities.
Debate on overhauling the Council has been gathering momentum for years. While the United States earlier this year backed broadening the line-up, Britain remained defensive. Its spot on the P-5 was arguably one of the last legacies of empire.
This morning, Robin Cook, the Foreign Secretary, will signal a change. In his debut address to the annual meeting of the UN General Assembly, he is set not only to voice support for reform of the Council but to ask that it be agreed quickly, if possibly by the end of the year.
His appeal will form part of a wider pitch for progress on all fronts of UN reform. He is expected strongly to back the package for change unveiled by the Secretary General of the UN, Kofi Annan.
Mr Annan broke with tradition yesterday by delivering a speech before the start of the general debate in the Assembly, which is led by foreign ministers from all 185 member countries and, in the case of the US, by President Bill Clinton. In it Mr Annan pleaded for backing for his reform drive. "Let this be the Reform Assembly," he declared.
Mr Annan's proposals - his "quiet revolution" - aim to streamline the UN bureaucracy and direct money saved from administrative costs to development projects. The other main planks of the reform agenda are restoring the UN's financial health and revamping the Security Council.
Following America's lead, Mr Cook will nominate Germany and Japan as two clear candidates for permanent spots in the Council. Officials indicated, however, that he will steer clear of the potentially intractable issue of which Third World countries may be offered three more permanent seats.
Yesterday, President Clinton told the Assembly progress was being made towards persuading the US Congress to release at least a portion of the roughly $1.5bn Washington still owes the UN. As much as $900m could be paid if a recalcitrant Congress acquiesces.