In our weekly legal column, the Leader, with the expert advice of the team at GHP Legal, sets out to answer some of your problems. Today's question is answered by partner Ulia Choudhry...

Can Nil Rate Band IHT be transferred to more than one surviving spouse?

Q: My stepfather died earlier this year. He left sums of money to his two stepchildren from his first marriage and everything else to my mother. However, a large proportion of his Nil Rate Band (NRB) exemption allowance went unused. I have tried to explain to my mother that she can get it transferred to her, as the surviving spouse. Now she is wondering whether she should have done this when her first husband (my father) died back in 2007 as he also had unused NRB.

A: It is perfectly possible for both your father and your stepfather's unused NRB to be transferred to your mother. However, whether their unused NRB can be transferred in entirety will depend on exactly what percentage remained unused in both cases, as there is a restriction of 100% total that can be transferred. You should also bear in mind that NRB allowances have changed in the time between your father dying and your stepfather dying.

Any claim for the transfer of unused NRB can, however, only be made upon the death of the surviving spouse, which in this case is your mother. When that time comes the executors of your mother's Will should complete form IHT402 which they can download from the HMRC website. They will have 24 months from the end of the month in which your mother died to do this. They will need to attach a copy of a grant of representation or confirmation and copy Wills, along with copies of the relevant death certificates.

If the transfer claim is valid, the NRB of the surviving spouse is increased by the proportion of the NRB unused on the first death, even if that person has been married more than once and irrespective of the size of the estate of the first deceased. As you can see, this can be complex, so it would be wise to seek advice and help from a solicitor.

• This question has been answered by Ulia Choudhry, a partner with GHP Legal. If you would like to speak to someone about this or any other legal matter, please visit our website www.ghplegal.com and use the contact us form, or call us on: Wrexham 01978 291456, Llangollen 01978 860313, Oswestry 01691 659194.