"The idea of hereditary legislators is as inconsistent as that of hereditary judges, as hereditary juries; and as absurd as an hereditary mathematician, or an hereditary wise man; as absurd as an hereditary Poet Laureate." So wrote Tom Paine in The Rights of Man as long ago as 1791. Reform of the House of Lords is not a new issue. While this Government has made significant progress, successive governments have failed to resolve the matter. We are trying to reach a consensus on a way forward.

It is important therefore to acknowledge the areas where there is agreement. Most people agree that we should have two houses of parliament. Only smaller countries with homogenous populations seem to successfully operate a system with only one chamber. The important revising work of the Lords, improving legislation and bringing to bear expert and informed opinion on a wide range of topics, is acknowledged. Elected Members of Parliament take a strong line, illustrated most recently in an article by Gordon Brown, that the primacy of the Commons is of paramount importance. Similarly, there are few today who support the hereditary principle as a way of deciding who should make our laws.

Progress has been made. The majority of hereditary peers no longer legislate. Prime ministerial patronage has been reduced, transferring powers of appointment to other party leaders and the House of Lords Appointments Commission. But there is more to do. No one would suggest that the present House of Lords is the product of logic. It is a product of history, some might suggest an accident of history. The make-up of the Lords is irrational. No one drawing up a new constitution would construct an upper house in this way. But I recognise this has brought benefits.

It has prevented serious conflict between the two Houses. When there are disagreements, the unelected Lords should, in the last resort, give way. The powers of the Lords are, in any event, circumscribed by the Parliament Acts of 1911 and 1949. Since 1945, the Lords have generally voluntarily limited their powers further through the Salisbury Convention which holds that a proposal in the manifesto of a government party should be accepted as having been approved by the electorate, and therefore neither be rejected or changed out of recognition by the Lords. Until recently such conventions were regarded as having virtually the status of law. Recently, however, Liberal Democrat peers have decided, for reasons of their own, that they can abandon such conventions at will. This means we are in uncharted constitutional waters.

Yet without the hereditary peers we would have an all-appointed chamber. Such arrangements are understandably criticised. It does raise important questions of democratic legitimacy.

This has led to suggestions for a hybrid House where some members are appointed and some are elected. The track record of such hybrid arrangements is not encouraging. Members of the Scottish Parliament, where some are elected from constituencies and some come from a party list, complain about the difficulty of reconciling their different status. This was also the motivation behind the amendments to the Government of Wales Bill to prevent those defeated in constituency elections from being elected on a party list.

Having elected members in the Second Chamber, many of them probably politicians who were unable to get seats in the House of Commons, would change the entire nature of the legislature. We only have to look to other nations, such as Italy, to see there are real dangers in having two rival elected chambers at permanent loggerheads.

There has never been a consensus on how to reform the Lords. As long ago as 1911, the preamble to the first Parliament Act described it as an interim measure. That interim measure persists to this day. One of my predecessors, Richard Crossman, made clear in his Diaries that the main obstacle to reform was a lack of agreement on the powers and the composition of the Second Chamber.

The debate on powers could be resolved by making established conventions, such as the Salisbury Convention, legally binding to ensure the primacy of the Commons. This would have to be done by statute, and would be a complex process, but would assist in encouraging support in the Commons for changing the composition of the Lords. One thing is quite clear from the perspective of Members of the House of Commons. We must clarify and circumscribe the powers of the Second Chamber before deciding its composition if we are to achieve consensus among elected parliamentarians. And we must finish Tom Paine's unfinished business and end the anomaly of hereditary peers sitting in the upper chamber.

Geoff Hoon is Leader of the House of Commons