Can’t say it any better than the Indpendent does:
No picnic, car journey or bed and breakfast stay is truly complete without the blanket. This sometimes itchy sign of our defiance of all things European is our woollen riposte to that foreign invader, the continental quilt, the very name of which implies a deep distrust. What other piece of fabric could serve as a lunch table, be used to warm a grandmother’s knees and provide your bedding. We certainly didn’t build an empire toting around something stuffed with goose feathers which required a “tog rating”, whatever that is.
Here in the US few people I know of have picnics on a regular basis, yet I can’t see how anyone in Great Britain could refuse one, except under the threat of rain.
And to save you the trouble, if you don’t know what a tog rating is, it’s the measure of warmth of a douvet (comforter). The higher the tog rating, the warmer it is. The rating scale goes from 4.5 up to 15.