It is probably a good job that Nestlé changed to using only natural occurring food colourings in Smarties. I have no idea the effect a large (170g) tub of all blue Smarties coloured using E133 would have on me but I feel better knowing I'm eating seaweed instead -- the new blue colour is derived from cyanobacteria spirulina.
Possibly even better than a whole tube of naturally coloured blue Smarties is the tube they are in. They are in a proper Smarties tube with a blue plastic lid. Strangely it doesn't have a letter on the lid but a turtle instead.