The creator of this confectionary bar (Jasper T. Rolo) developed Rolo’s in the UK by Mackintosh’s, (later Rowntree-Mackintosh), simply Mackintosh’s Toffee coated with chocolate, they were first sold in 1937.
They were also produced in Norwich until 1994, when all UK production moved to Fawdon in Tyneside, by Nestlé Rowntree. There have now been Rolo biscuits, ice-cream, muffins, birthday cake, desserts, cake bars, doughnuts, mini Rolos, big Rolos, (all of which use the same type of caramel) yogurts and Easter eggs made. In May 2011, McDonald’s combined chocolate pieces and caramel sauce with their soft-serveMcFlurry product to simulate the Rolo flavour profile in a cross-branded product.
Info gleaned from Wikipedia