They were first produced in 1932 by William McDonald, a biscuit manufacturer in Glasgow, and became a McVitie’s brand when McDonald joined with McVitie’s and Price, MacFarlane Lang & Co and Crawford to form United Biscuits in 1964.
Each wrapper has a joke or “funny fact” printed on it and imaginative, often humorous designs featuring penguins that often pastiche famous works of art.
Penguins have been the subject of a court case between Asda and United Biscuits who accused Asda of passing off their own brand “Puffin” biscuits as part of the Penguin brand. The court found in favour of United Biscuits regarding passing off, but found that Asda had not infringed the Penguin trademark. United Biscuits itself has been criticised for continuing to use trans fatty acids in the cream filling of Penguins. By 2007 United Biscuits began to advertise the absence of trans fats from the penguin, having removed the ingredient from this product line.
Info gleaned from Wikipedia