From
GANSG - Bread and cakes
Turog bread was introduced to the UK in 1903, as with Hovis the flour was sold to local bakeries who were then allowed to advertise. Turog supplied its shops with a 3-D sign made of bass relief lettering on a metal frame to mount on the outside wall, the same style of lettering was also used for painted signs on the walls of the bakers.
They had a factory in Cardiff and were a national brand by the 1950s.
And here's a lovely photo of an old sign:
Turog Bread Sign. Uppermill. | Flickr - Photo Sharing!
Sounds like a Welsh word to me - and the bakery at Cardiff's folk museum is called Turog
Turog Bakery - Cardiff - Bakeries
Can't say I've ever heard of the bread Keith mentions - or the crude song!