The Labour Party put Taito Phillip Field behind it some time ago. But there will still be relief in party ranks at yesterday's guilty verdict which - barring possible appeals - brings an end to this embarrassing episode in Labour's recent history.

That Field has been found guilty on charges of bribery and corruption as an MP and wilfully attempting to obstruct or pervert the course of justice removes any lingering possibility that he might have retained of becoming a martyr figure at Labour's expense.

That does not absolve Labour for its shoddy handling of the corruption allegations levelled at Field in 2005 after stories that - as junior immigration minister - he had helped would-be immigrants with their cases for residence in return for them doing work on his homes in New Zealand and Samoa.

Then Prime Minister Helen Clark stood Field down as a minister and appointed Noel Ingram, QC, as a one-person inquiry. Ingram's report raised extremely serious questions about Field's behaviour and should have been immediately referred to the police.

Apart from slapping Field across the wrist for making "errors of judgment", Labour instead held its nose and stuck by him for fear of alienating its large Pacific Island vote. Labour was wary of provoking him into holding a byelection in his Mangere seat. Crucially, he also held a casting vote in Parliament .

But the police began their own investigation. The smell would not go away and he was expelled from Labour after he made a few rash comments about possibly running against the party in last year's election.

He ended up doing exactly that. He lost heavily in Mangere, but his New Zealand Pacific Party still picked up more than 8500 party votes nationwide.

Most of those presumably came from Labour. But that party paid a bigger price by being tainted by association with Field. He became one more element in the picture National painted of a Government fast-approaching its use-by date.

Like Donna Awatere-Huata, Field's legacy will be as another illustration that no MP is above the law. However, his behaviour did not end up prompting what some MPs had hoped it would - a members' code of ethics.

The biggest lesson may be to prime ministers to be more careful about playing politics when it comes to setting up inquiries. Labour thought it could get the outcome it wanted by limiting Ingram's ability to investigate the allegations against Field.

Despite that handicap, Ingram produced a report which was damning of the MP. Ingram can hold his head high. The QC is alone in emerging from this affair with his credit enhanced.