So how did they get here? How have clever people who hold senior MP and even Cabinet jobs found themselves taking such a hammering over their expenses claims?
And why have Stormont politicians also been facing flak about their allowances and salaries?
The answers can be found in a series of issues, some of them with Northern Ireland dimensions.
The recent rash of adverse headlines about Westminster expenses has largely concerned one particular area of MP remuneration.
It used to be called the “Additional Costs Allowance”, but now has the even less snappy title of “Personal Additional Accommodation Expenditure”.
Currently worth up to some £24,000 a year, it is designed to cover MPs' costs while staying away from their main homes on parliamentary business.
This can cover mortgage interest payments on a property — leading it to be dubbed the “second homes allowance”.
It can alternatively be used to cover rental or hotel costs.
Claims can also be made for electricity, water and gas bills, furniture, household electrical appliances, telephone and TV services, decoration and repair costs, insurance, cutlery, cleaning and basic security measures.
It was under this allowance that Home Secretary Jacqui Smith claimed for such items as an 88p bathplug, a £2.50 toothbrush, a barbecue and — inadvertently — two pay-per-view porn movies purchased by her husband.
The “Personal Additional Accommodation Expenditure” also provides a flat-rate sum of £25 for any night an MP spends away from his or her main home on Commons business.
Controversies about the allowance include the fact that it is available to MPs from outer London constituencies.
That means an MP can claim for mortgage interest payments for a property in central London, while representing and living in a district within commuting distance of Westminster.
Additional accommodation cost payments have also been made to Sinn Fein MPs for a number of years, despite the fact that they do not take their Commons seats.
The party's five MPs — three of whom are also Stormont Ministers — claimed just over £105,000 between them under the allowance in 2007/08, funding the rental of two London flats.
The Conservative Party has pledged to end the payment of parliamentary expenses to abstentionist MPs.
A separate area of controversy involves MPs being permitted to claim the full London accommodation expenses, while sharing properties.
Sinn Fein's MPs fall into this category, as do husband and wife MPs including the DUP's Peter and Iris Robinson.
Each of the Sinn Fein MPs received fairly close to the maximum in 07/08, with some £21,000 each.
Mr and Mrs Robinson claimed £40,342 between them under the allowance in the same year.
The DUP couple purchased a £450,000 apartment in London's Docklands area in 2001.
Other husband and wife teams in the Commons include government ministers Ed Balls and Yvette Cooper.
In a report last autumn, Parliamentary Standards Commissioner John Lyon recommended a cut in the individual allowance for MPs sharing properties.
He stated: “Members sharing properties should have outgoings that are less than double that of a single Member to provide the same standard of accommodation and services.
“What a reduced shared allocation should be is a matter for further examination by others. Nor would I confine this only to Members who are married couples or who are the partner of another Member.
“It seems to me that once Members share properties with each other, even if they do not share other aspects of their lives, they should have a sharers allowance which is less than the sum of the allowances available to each Member singly.”
That proposal is expected to be examined when the “Personal Additional Accommodation Expenditure” comes under scrutiny as part of a wider inquiry into MP remuneration.
It will be conducted by the Committee for Standards on Public Life, which plans to issue its report by the end of the year.
Before then, Parliament should have finally made a long-awaited disclosure of all expenses claimed by MPs in recent years.
It will involve an item-by-item, receipt-by-receipt breakdown with a level of detail similar to the recently leaked material about Jacqui Smith.
The Commons fought hard, but ultimately unsuccessfully, against the release of all this material under freedom of information.
It now appears to be planning to publish it in mid-July — leaving it open to the accusation of “burying bad news” in a quiet news period.
On this side of the water, meanwhile, the Northern Ireland Assembly has separate expenses questions of its own to tackle.
The issue of double jobbing by Stormont politicians has now been pushed well up the political agenda.
The Scottish Parliament has just one member — First Minister Alex Salmond — who is also an MP.
At the Welsh Assembly, there are no such double jobbers.
In stark contrast, 16 of Northern Ireland's 18 MPs are also senior Assembly members.
There are even cases of triple and quadruple jobbing — involving MLA, MP, councillor and Stormont Minister or Assembly committee chair roles.
A decision will have to be taken at some time on recommendations published last December by the London-based Senior Salaries Review Body (SSRB).
This officially commissioned report proposed a £3,000 wage rise for Assembly members phased in over a four-year period.
That is highly likely to be |rejected, as MLAs are well aware that it would play very badly with voters.
But the SSRB report also addressed the contentious topic of double jobbing, and recommended a significant expenses cut for Assembly members who are MPs.
They currently receive some £73,000 a year from Stormont for office-running costs, plus more than £100,000 from Westminster for the same purpose.
Critics argue that this gives an unfair advantage to the politicians by bankrolling large-scale staffing and advice centre operations.
Under the SSRB's plans, the |annual Assembly total would be cut from £73,000 to £35,000.
However, it is by no means certain that this will be accepted at Stormont.
Meanwhile, the Assembly also has to face up to other expenses issues raised in the SSRB report.
It remains to be seen whether Stormont will move towards new independent audit oversight measures — like valuation checks on constituency offices being leased at public expense.
Another possible option would involve placing a size limit on the taxpayer-funded MLA offices.
Disparities still remain, meanwhile, between the rules at Stormont and those in force at Westminster.
MPs with family members on their staff teams have to publicly declare the details in the House of Commons register of interests.
There is currently no such requirement for MLAs.
It is also still permissible for Assembly members to rent constituency offices from their relatives.
On another front, the Code of Conduct for Stormont Ministers contains no internal mechanism for assessing complaints about alleged non-compliance.
It appears to some observers that the powers-that-be here are reluctant or unable to seize the initiative on pay and expenses questions.
That same criticism has been directed at the Westminster establishment, amid all the rumpuses there over the past couple of years.
Some of them may be finally “getting it” — at long last understanding the level of anger among voters.
Others are still clinging to the notion that it's all being whipped up by the media.
They have obviously not been paying attention — to the radio phone-ins, to the newspaper letters pages and to opinion poll findings.