Even by the DUP's standards, Mrs Robinson's politics comprise an unpleasant concoction of bigotries, seasoned with a predictable dash of ethno-religious fanaticism.

This unpalatable dish is served up with a sizeable side-dollop of spite, epitomised by Iris's triumphant nine-finger salute which taunted Tory MPs after DUP votes had secured a Government victory on 42-day detention, or by her serial "unparliamentary" harassment of the Health Minister, Ulster Unionist Michael McGimpsey, for which she attracted official censure.

It is possible, of course, to elicit human sympathy for Robinson in light of the mental illness which has forced her to step back from her duties. Perhaps the condition might even permit a kinder interpretation of the extremity of some of her outbursts.

But the sum total of hatred and intolerance encompassed by Northern Ireland's politics will be diminished by Iris Robinson's retirement and that is not a result to lament.

She is one of a small number of DUP politicians, Sammy Wilson - the climate sceptic who served as Northern Ireland's environment minister - is another, whose reactionary opinions have been scrutinised with horror by the national media. In Robinson's case, her dehumanising attitude to homosexuality attracted widespread opprobrium and the gay rights association Stonewall named the MP its Bigot of the Year for 2008.

Informed by a fundamentalist interpretation of Christianity, the Strangford politician's arguments on the gay issue were a rather confused mishmash.

She claimed homosexuality to be an "abomination" and compared it to child abuse, stating that there "can be no viler act", yet on the BBC's Nolan Show she suggested that gay people are mentally ill, recommending a psychiatrist with a record of "turning" homosexuals.

Setting aside the unscientific nature of this proposition, surely experience of a mental illness would have cautioned Robinson against describing its sufferers as "vile" or claiming that they made her "sick"? Her language revealed a startling lack of empathy for fellow human beings.

Robinson's intemperance was not reserved for those who offended her religious sensibilities. As a health spokesperson at Stormont she clashed repeatedly with Michael McGimpsey and seemed unable to restrain her temper.

During 2007 the Speaker - and DUP MLA - Willie Hay banned Robinson from the Assembly for a day after she lambasted McGimpsey in an "unparliamentary" outburst.

Earlier this year, in another disproportionate attack, she called on the Health Minister to resign after he revealed that adequate funds were not available to send children suffering from epilepsy to the United States for treatment.

As an MLA, health spokesperson, councillor and MP, Iris Robinson certainly undertook an unforgiving workload.

However, in spite of a patchy attendance record at the House of Commons, Iris attracted disapproving headlines for Westminster expense claims, submitted alongside her First Minister husband. They managed to munch through £30,525 of food over a period of four years, which they subsequently claimed from the taxpayer.

Iris Robinson deserves support as she attempts to recover from a debilitating condition. Most people in Northern Ireland will be all too aware of the damage which depression, and other mental illnesses, can inflict upon friends and family.

We can, however, extend the Strangford MP sympathy and good wishes without applauding an erratic and unconstructive political career, occasionally characterised by a vicious and vindictive use of language.