Dessertspoon English measurment

[Nanalovescooking]

I have several English cookbooks. Some of the recipes say to add, for instance; 1 dessertspoon of sugar. I have both a tablespoon and a dessertspoon (not measuring spoons) that I brought back from England some years back, but cannot remember which one I should use in the recipes asking me to add a dessertspoon of something. I have looked on the internet, but have found no clear answer.
Thank you for your help with this.