When an ex-husband or ex-wife dies, make sure you check the grant of probate or letters of administration to see how much he or she was actually worth at the time of death.
It may be that there are extra assets that you were not aware of at the time of divorce, so if you have been awarded maintenance based on the asset level at the time of divorce, you could claim more if these assets have substantially increased.
Under the Inheritance (Provision for Family and Dependants) Act 1975, a spouse is liable to make reasonable financial provision for a spouse or former spouse who has not remarried. If you discover that there were assets passing under a will, or held in trust offshore or onshore, then you can claim for a higher portion of the estate than you were awarded on divorce.
If you are still married to the deceased and you believe that you have been unfairly treated you can also bring a claim. The award that will be made should be similar to the award in a divorce, although the recent Lilleyman case has thrown some doubt on this (see Lilleyman v Lilleyman (2012) EWHC 821 (Ch).
Don’t delay though, because you have only six months from the date of the grant of probate to bring a claim, although in certain circumstances it is possible to ask for an extension.