Freedom is one of mankind's fundamental treasures. Without it, health and prosperity cannot bring happiness. That is why Britain was prepared to sacrifice hundreds of thousands of lives in the Second World War. The basic expression of freedom in our country is the ability of ordinary citizens to dismiss an unpopular government by voting in a general election.

Old ways are the best: Alternative Voting throws up more questions than answers and would keep the Lib Dems in power, no matter who won the most seats (Getty Images) 

The removal van that comes to the back door of Number 10 Downing Street to collect the possessions of the prime minister on the morrow of the ruling party's electoral defeat is the prime symbol of our liberty. Elections have a number of functions but "throwing the rascals out" is the most important. However popular a new premier and a freshly elected government may be, there frequently comes a time for a change. That change may come about in a whole variety of ways. Margaret Thatcher was forced out of office in 1990 by a rebellion of Conservative backbenchers. In Europe, coalition governments fall typically as a consequence of quarrels and backroom dealings in the ruling circle of politicians. Elections and electors have only an indirect role in determining who governs. In a true democracy, the ousting of the executive should be the prerogative of the electors.

Yet this precious prerogative is under threat. The danger to the system of "removal van democracy" is insidious because the threat does not come from the ranting of a foreign dictator, from natural disaster or from economic crisis. It is hardly noticed, highly technical and — let's face it — boring. Few people know what the "Alternative Vote" is. Even fewer care. Electoral reform and its many variations are the passion of small groups of political scientists and sundry campaigners — mostly with Liberal Democrat interests. They have gained a disproportionately great influence because they have caught the great British public napping.

It is curious that Britain's first national referendum for 35 years will be on such an obscure topic as the Alternative Vote. Even professional commentators know almost nothing about AV, as some of them readily admit. I doubt whether our top politicians know much about it either. 

Apart from biased explanations from specialist groups linked with the Lib Dems, which have been lobbying for decades for voting reform, virtually no information is available on the meaning of the term "Alternative Vote" let alone on its pros and cons. The Parliament and Constitution Centre of the House of Commons Library, which is the country's most authoritative source of information about constitutional questions, failed in its recent Standard Note on the Alternative Vote to cite any neutral source in its list of pros and cons. It merely quoted a publication of the Electoral Reform Society. Since the society is devoted to campaigning in favour of electoral reform, it is hardly a reliable fount of information about the objections to it.

The case for voting against AV rests on three clusters of arguments: the flawed process which led the referendum to be called in the first place and the senseless hurry to push the Parliamentary Voting System and Constituencies Bill through Parliament; the big-picture arguments against voting reform; and the technical ambiguities and defects of AV itself.

There is a continuing and fascinating debate about the political wisdom of David Cameron and his team in entering so wholeheartedly into coalition with the Lib Dems after the inconclusive 2010 general election. Only time will tell if this was a masterful gamble that will transform the future of British politics and create a realignment enabling the Conservatives to regain their historical status as the natural party of government. Given the huge political prize of a stable Con-Lib coalition, it was arguably a small concession to offer the Lib Dems a referendum on the mildest possible form of change to the voting system — AV.

However, the British Constitution is of such fundamental importance that it is far from ideal to endanger it for the sake of an inter-party deal, no matter how attractive. A constitution should be stable and be altered only when there is a pressing reason for doing so and demand for change from a clear majority.

During the election campaign, a mere one per cent of the population — as measured by Ipsos MORI — rated constitutional reform as the most important issue facing the country. Since AV was merely one of a number of aspects of constitutional reform, it is reasonable to conclude that only a small proportion of this one per cent rated a change to this system as the key matter. There is no mandate for pushing a referendum on AV to the top of the political agenda.

If there is to be such a referendum, there is a strong argument for holding it only after the details have been worked out and approved by both houses of Parliament. Instead, at the Lib Dems' insistence, the date has been set for May 2011. This will leave no time to debate properly the many outstanding details about the wording of the referendum question and the rules for its administration and financing. The Lib Dems' motive for holding the referendum so early is clear from research by Dr Matt Qvortrup of Cranfield University showing that referendums are far more likely to win public approval if they are held during the honeymoon period shortly after a general election.

Leaving aside the legal problems about referendum funding left by the hastily-enacted Political Parties, Elections and Referendums Bill, 2000, and ignoring too the problem posed by the fact that the chair of the Electoral Commission is a former employee of a voting reform lobby, there is the matter of the wording of the referendum question itself. The coalition's political leaders have set out a form of words that asks the country to decide between the "Alternative Vote" and "First Past the Post". Yet the term "AV" itself is ambiguous. Under some forms, an elector is obliged to list all the candidates in a constituency in order of preference. Unless he or she does this, the ballot is invalid. Under other forms of AV, the voter needs to make only as many choices as desired. The two systems work very differently and raise separate questions of principle. Yet, the wording of the referendum question leaves open which form of AV is up for approval. Nor are these the only two forms of AV.

Turning from the flawed process of constitutional reform, there are several substantial objections to AV. 

Australia is the only established country to use AV for elections to the lower legislative chamber. The obscurity of the other examples — Fiji, Iraq, Nauru and Papua New Guinea — should be a cause for concern not least because of the continuing problems in Fiji. It is significant that Australia's neighbour, New Zealand, has not even included AV among the list of options for a referendum on voting reform it is due to hold in 2011.

In practice, AV would not be the real issue in the proposed British referendum. It would be naive to imagine that the ambitions of the main party in the Commons to favour change in the electoral system — the Lib Dems — would be satisfied by a change to AV. Although its political effects are unpredictable, it would be likely to give them some 20 more seats and the Conservatives about 20 fewer, thereby making another hung parliament more likely. Conservative MPs would be especially vulnerable in constituencies in which the Lib Dems were the main challengers. 

In the likely eventuality under AV of a further hung parliament, the Lib Dems would then demand full PR as the condition for their participation in another coalition government. So, it is realistic to treat AV as the stepping-stone to proportional representation.

AV — and still more PR — make it far harder for voters to dismiss a government. With a multiplication of political parties, governments will be formed and dismissed not by the voters but as a result of private deals between politicians. These deals may be about sensible compromises about policy. They also may be squalid bargains about patronage and the disposition of the spoils of power. 

For all its admitted statistical imperfections, the Westminster model delivers the essential feature of democracy: the capacity of electors — not of cabals of politicians — to hold a government to account. Once a prime minister feels that it may be possible to escape the verdict of the electors by doing a post-election deal, the quality of democracy is undermined.

Following electoral reform, the Lib Dems would virtually always be in office. General elections would decide whether the Lib Dems would join either the Conservatives or Labour in a coalition. The Lib Dems would be almost immune from the wrath of the electors for, even if they lost votes, they still would belikely to hold the balance of power. We are used to a system that has discriminated against the third party. But a new voting system that made it virtually impossible to remove it from office would be far worse. 

If, as is likely, AV led to PR, then extremist parties would gain. This may be why "Unlock Democracy", one of the main pro-voting reform lobby groups, benefits from the leftover funding and property of the defunct Communist Party of Great Britain.

At a technical level, AV has multiple problems leading to frequent spoiled ballots.

If (as in Australia) electors are obliged to list all the candidates in order of preference, they thereby are forced to give a measure of support to representatives of parties they may abhor. For if there is a far-Left and a far-Right candidate on the ballot, the voter must choose one over the other. Moreover, a ranking of fourth and fifth choice candidates may have a considerable effect on the outcome of a close constituency contest. 

AV has mathematical quirks. When the second, third and fourth preferences of the lowest-scoring candidates are redistributed until one candidates wins at least 50 per cent of the votes cast, the winning candidate cannot thereby be guaranteed to enjoy the votes — even the lower preference votes — of a majority of the electors. Voting-reform schemes involving complex formulae for calculating election results deserve to be treated with the same caution as financial products that can barely be understood. There is usually a hidden catch. 

In the case of the referendum on AV, the Lib Dem leader falsely represented it to the House of Commons as a response to the scandal about MPs' expenses. It has nothing to do with that scandal and would intensify the very problems that led to it.

Nick Clegg spoke about the need for "transferring power away from the Executive to empower Parliament, and away from Parliament to empower people." Yet, a move away from the first-past-the-post system of elections for the Commons would rob ordinary voters of their core power — that of removing an unpopular government from office by their votes at a general election. In its stead, Clegg advocates a voting method that would permit his party to hold the balance of power and to assure himself a place in government virtually in perpetuity. This is attractive for Clegg but is hardly a model of elective democracy.