Amid all the political comings and goings of recent weeks, something that has been ignored by the media and politicians is the importance of observing those conventions which have such an important place in the constitutional arrangements of the UK. In Some Problems of the Constitution, Geoffrey Marshall and Graeme Moodie defined conventions as ‘rules of constitutional behaviour which are considered to be binding upon those who operate the constitution but which are not enforced by the law courts’.

The first convention that has been overlooked is one of the most basic features of our unwritten constitution, namely that the Queen will appoint as prime minister the person best able to command the confidence of the Commons. One of the reasons it is said that Labour MPs pulled back from toppling Gordon Brown was that any new prime minister would be constitutionally obliged to ask the Queen for a dissolution of parliament, so that a general election could take place.

Such a proposition is incorrect. If, for example, Alan Johnson had become Labour leader (and therefore prime minister), provided he was able to command the confidence of the Commons, there would be no constitutional ‘peg’ on which demands for a general election could be hung.

Thirteen previous prime ministers came to office without having been put there by the electorate. Also, the purpose of a general election is not to elect a prime minister. The purpose of a general election is for each parliamentary constituency to elect an MP to represent it at Westminster. The prime minister will be the leader of the political party which gains the majority of seats in parliament at the general election.

That does of course leave the question of how such a situation would play in Harriet Harman’s ‘court of public opinion’. Would the public accept as prime minister someone whom they had not voted into office? The answer, almost certainly, is yes. Despite the protestations of David Cameron and Nick Clegg, there is little public appetite for a summer of electioneering when a general election must, in any event, take place no later than mid-2010.

The second convention that has been ignored is that senior government ministers should be members of the democratically elected Commons as opposed to the unelected Lords. The culprit this time is Brown, whose purported desire to modernise the constitution should be viewed against the backdrop of his promotion of the recently ennobled Lord Mandelson of Hartlepool and Foy.

Nine months ago, Peter Mandelson (as he then was) was EU trade commissioner. He has now been given the title of first secretary of state, as well as being secretary of state for business, innovation and skills. He is, in all but name, deputy prime minister and is second only to Brown within the cabinet hierarchy. This is a dangerous development. The purpose behind this convention is to ensure that senior government ministers are democratically elected and can be held properly to account for their actions by the Commons. While, even in recent governments, a number of ministers have been members of the Lords, none of these ministers has exercised anything like the power or influence which Lord Mandelson now has at his disposal. Nobody voted for Lord Mandelson and he need only answer ministerial questions in the sedate atmosphere of the Upper House rather than the more combative arena of the Commons.

If Brown were suddenly incapacitated, it would be Lord Mandelson as first secretary of state who would head the government during Brown’s absence. In The Law and the Constitution, Sir Ivor Jennings famously described conventions as ‘the flesh that clothes the dry bones of the law’, suggesting that conventions were what made our unwritten constitution workable.

Recent events would suggest that the flesh, while not rotten, is beginning to sag a little. At a time when public respect for parliament is in short supply, those in government would be wise to heed the importance of observing conventions.

Gary Atkinson is senior lecturer at the College of Law