First Minister Peter Robinson faces a major expenses blow after it was announced that MPs are to be barred from claiming expenses for second homes and will be limited to employing no more than one family member.
The move will affect Mr Robinson, whose second home in London is paid for by the taxpayer.
Mr Robinson has also employed his daughter, Rebekah, as his office manager and private secretary, while his son, Gareth, is his parliamentary assistant.
The new expenses scheme for the House of Commons drawn up by the Independent Parliamentary Standards Authority (Ipsa) will come into effect immediately after the general election and will allow MPs only to claim for rented accommodation.
MPs will not be eligible for accommodation expenses if any part of their constituency is within 20 miles of Westminster or inside a 60-minute commute by public transport.
In a a tersely-worded email to a member of the public defending his expenses claims last May, Mr Robinson said: “I make no apology for employing my own family and those who are the family of friends.
“I have been an elected representative for more than 30 years and have worked through the conflict that our society has faced. Those who work in my office know where I am and when I will attend meetings and events. I am not prepared to employ by open competition.
“My life depends on those who I have around me but, even if it were not so, there are distinct advantages in employing those who are completely loyal and in tune with the position I adopt.”
Launching the new system in Westminster yesterday, Ipsa chairman Sir Ian Kennedy said the maximum MPs will be allowed to claim for accommodation and constituency office costs each year will be cut from £56,915 to £40,957 for MPs outside the London area and from £40,192 to £26,915 for those in and around the capital.
Sir Ian said: “The new system is fair, workable and transparent. It will enable MPs to carry out the job we ask them to do and will provide reassurance and value for money to the tax-paying public.
“No longer will MPs benefit from a slack allowances system. This system brings MPs' expenses into line with those in most other areas of life.
“Expenses will be reimbursed only for legitimate costs, backed up by receipts.”