Is it correct that I don't need a Will because if I die everything will go to my husband/wife/civil partner anyway?

Not necessarily - the Rules of Intestacy say that the surviving spouse/civil partner only takes £250,000.00 of free estate if you leave children and £450,000.00 of free estate if you leave parents or siblings - if you own a property in your sole name these limits can soon be achieved and you will leave your spouse/civil partner in a mess.