If you don't make a Will your spouse, civil partner or partner may not get what he or she is expecting. Civil Partners are treated as if they were married. The Rules of Intestacy determine how your estate is to be distributed after the payment of all your debts and liabilities, testamentary expenses and funeral costs.
An estimated two thirds of people never make a Will. They are often surprised to learn that loved ones do not automatically inherit. In particular, a live-in partner (not in a registered civil partnership) would receive nothing at all as of right. This is because the Rules of Intestacy do not recognise 'unmarried partners' (although civil partners are treated the same as spouses) and therefore no provision is made for them. Making a Will can remove much of the unnecessary worry and problems you could leave behind and can also reduce your family's liability to Inheritance Tax.
Without a Will, the spouse or civil partner would get the first £250,000.00 of any amount and interest on half the balance. The remainder would go to the children. If there are no children the spouse will receive the first £450,000 and half of the remainder with the balance going to any surviving parents or brothers and sisters.
As more and more houses are now exceeding the £250,000.00 limit it could well be that the spouse could not continue to live in the house without the consent of the children - which might not be given.
As far as a partner is concerned they may or may not have a claim against the Estate and it is clearly sensible to say what you want to happen in your Will.
If you make a Will you can decide how your Estate is to be divided up.
Sadly people often don't get around to making Wills usually because there are family issues which cause them concern and which they don't wish to confront. However if they do not confront them then someone else will have to!