The Big Question: Should MPs' expenses and allowances be subject to tighter controls?

Why are we asking this now?

Derek Conway, the Tory MP who stands accused of abusing the expenses system by over-paying his two sons for research work, has had the party whip withdrawn from him by David Cameron. Yesterday, with his career in ruins, he said he would not stand for re-election in his Old Bexley and Sidcup constituency. Mr Conway has apologised, but that has not stopped fresh complaints about a lack of transparency in how MPs run their offices. Some critics have called for tighter checks on how MPs use their expenses entitlements, which remain a mystery to much of the public. The chairman of the Committee for Standards in Public Life has even mentioned the idea of a total ban on MPs employing relatives.

What is Mr Conway accused of?

The current rules do not ban relatives of MPs from carrying out secretarial or research work for them, as is the case in the United States. The real problem for Mr Conway was that the Commons Standards and Privileges Committee could find no record of the work his youngest son Freddie had done to earn his £11,173 a year. He has also come under pressure for paying his eldest son Henry £10,000 as a part-time researcher, working just 18 hours a week. Some have defended Mr Conway, though. His fellow Conservative MP, Roger Gale, said that he had been the victim of a "witch-hunt", as Labour MPs latched on to the incident to deflect criticism of their own party over a spate of funding scandals.

What exactly can MPs spend on staff?

The current limit on spending on their office staff is £87,276. It has risen quickly, though. That's £10,000 more than two years ago, and it is set to rise further. Soon, they will have another £10,000 added to the maximum budget for secretaries and researchers, with the limit rising to £96,630. On top of the salary for their staff, they can also claim some of their travel costs.

Is Mr Conway alone in employing family?

No. Employing a wife, husband or child to work in their office is not uncommon among MPs. While that may sit uncomfortably with some taxpayers, even critics of the system suggest that the practice should not necessarily be ruled out altogether. Liberal Democrat MP and anti-sleaze campaigner Norman Baker, said: "It would be perverse to rule people out of doing a job. The issue is not who they are, but whether or not they are doing the job that they are being paid to do."

So as long as they're doing the job, is it ok?

Perhaps the practice of employing a wife (or husband, in the case of Margaret Beckett) as a secretary is accepted, but some see handing a close relative the job of researcher as a little more problematic. Being an MP's researcher is often a way of climbing the first wrung on the slippery political ladder, and the positions are much sought after by ambitious, young political minds. That places a greater need for transparent selection based on merit. Among those to have risen from the lowly researcher ranks is New Labour architect Peter Mandelson, now an EU commissioner. He had a stint as researcher in the office of Labour's transport spokesman, Albert Booth, in the early 1980s.

So what else are MPs allowed to claim?

Money allocated for employing office staff is the biggest bulk of an MP's allowances, but there are a number of other expenses that they can claim when entering Westminster. MPs from outside central London get an "additional cost allowance" to pay for staying away from their main home. It's effectively a second home subsidy, and is up to £22,110. Those with a constituency in London get a supplement to their income of up to £2,712. A few fortunate souls qualify for both schemes, though payments are not necessarily at the maximum end of the scale.

MPs also enjoy a number of other perks, such as an "incidental expenses provision", which covers costs such as office equipment, travel costs and accommodation. There is a reimbursement scheme for car use and trips to EU institutions. They can also ask for up to two printers and a maximum of five computers, but these are "on loan" to them. All those costs are designed to allow MPs to take care of their Westminster and constituency responsibilities. Without them, they argue, there would be no way they could represent their constituents properly.

Do MPs need to top up their salary?

With their latest 1.9 per cent pay increase, the annual salary for MPs will rise from £60,675 to £61,820. The increase was in line with the rest of the public sector, but the process of setting the level of pay is often criticised as MPs are effectively in charge of their own pay increases. Undoubtedly, though, they could earn more elsewhere in private business, and many argue that they have a huge workload. That doesn't stop some MPs earning considerable sums outside the House.

Who monitors how MPs use expenses?

MPs regulate themselves, under the guise of the Commons Standards and Privileges Committee, which examines any breaches in the parliamentary code of conduct. Some argue that such a self-regulating system has now been proved to be too weak. The independent Committee on Standards in Public Life, set up by John Major in the wake of a number of sleaze scandals, is limited in its power as it does not look into individual cases. Specific rules governing the employment of people within the offices of MPs have also been challenged. MPs are under no obligation to declare who is working in their constituency offices, or how much their staff are being paid.

Will the rules be altered?

Sir Christopher Kelly, chair of the Committee on Standards in Public Life, has said that the employment of relatives is an area in need of reform, even saying a total ban "could be the right thing to do". Norman Baker believes something could be done immediately. He wants to see the National Audit Office introduce "spot checks" on the offices of MPs, which would allow them to find out who is working there and whether they are carrying out the work that they are paid for doing. He suggested the random inspections should be made to five per cent of the offices each year. The Senior Salaries Review Body has also recommended that expenses claims without a receipt should be capped at £50. The current maximum is £250.

It is unlikely Gordon Brown will make any snap decisions over a rule change, but with so many people advocating a tightening of the rules, reforms might well emerge sooner rather than later.

So is reform necessary?

Yes...

* Derek Conway is not the only MP to employ family members, and the practice is banned in some countries

* MPs do not currently have to declare who they are employing in their offices

* The system is not independent enough, with MPs largely left to regulate themselves

No...

* Many spouses who work in offices have a very heavy workload and know the job better than anyone else

* The expenses system might seem generous, but MPs have a lot of travelling and extra outlay because of the nature of their work

* MPs could earn far more in private business, and further regulation into how they run their office could put more off the job