The House of Commons has had more than 150 Speakers since the role was created in 1376. Never has the choice of a new Speaker been more important than today, when Members of Parliament will decide which of 10 candidates will be installed in the green chair. Parliament has been defiled by more than a month of damaging revelations about allowances and expenses, and Michael Martin's successor must spearhead the challenging task of rebuilding public trust.

If, as was alleged yesterday, the election process has fallen prey to political factionalism and horse trading, it suggests MPs are still failing to appreciate the seriousness of their situation. If Labour members back the independently-minded Conservative John Bercow, merely to rile the Tory leadership, they are doing Parliament a great disservice. The same would apply to Tory members backing Labour's Margaret Beckett on the basis of "anyone but Bercow".

The new Speaker faces the difficult double challenge of making Parliament simultaneously meeker and stronger. First and foremost, the Commons must be restored to its proper place as the embodiment of the will of the people rather than a distant institution whose members are a law unto themselves. The new Speaker must be someone of integrity who both understands the damage done to parliament and possesses the skill and determination to push through major reform, dragging it out of the 19th century and into the 21st. She or he must have the leadership skills to preside over the transition to a new government and a large intake of new MPs.

If MPs elect Mr Bercow, it should be not for narrow political reasons but because he has a vision of the Speaker's role as a champion of the Commons' place in British democracy. He understands best the need to reconnect with the electorate.

Some candidates appear better suited than others to the immediate task of cleaning up MPs' expenses and allowances. Mrs Beckett, Labour's Parmjit Dhanda and Tory grandee Sir Patrick Cormack have all been touched by the scandal themselves. The two deputy speakers are tainted in the same way Mr Martin was. The candidate least caught up in this sordid business is perhaps Sir George Young, who is near the foot of the expenses league table. Would he have the necessary determination to resist moves from the Labour and Tory leaderships to water down reform? There must be no return to the dark arts.

The new Speaker must also champion the ability of backbenchers to hold the Government to account. This means dismantling the power of the whips, both in early readings of legislation and in choosing the composition of select committees.

Any Speaker requires a detailed knowledge of parliamentary procedure, but he or she must be prepared to ditch much of it. During this scandal the archaic language, processes and dress of Commons officials only served to emphasise the disconnection with the public. The unquestioned authority of the Scottish parliament's Presiding Officer shows such arcane trappings are unnecessary.

The other charge levelled at Speaker Martin was that he operated as a shop steward for MPs in sanctioning the harmful expenses blackout, having failed in court to secure an exemption to Freedom of Information. Yet the Scottish experience suggests that transparency is the best guarantee against abuses.

As well as restoring trust, the new Speaker must rediscover the strength of Parliament to resist the dominance of an executive that has been centralising power for 30 years and a civil service that could use Parliament's current plight to hijack policymaking. The Commons would seem more relevant if there were more ministerial statements and debates on topical issues.

The introduction of a secret ballot means there has never been a better opportunity to ditch narrow party politics and rally around the individual best equipped to put the House back where it belongs: at the heart of British democracy.