  We provide holographic realisations in Minkowski spacetime of a free
conformal Carrollian scalar field living at null infinity. To this end, we
first show that the electric and magnetic limits of a relativistic conformal
scalar are equivalent and we study the representation of the Carroll,
Poincar\'e and BMS algebras that is realised on the resulting solution space.
We then realise it as a quotient of the solution space of a free massless
scalar in Minkowski spacetime with unusual falloff, in full analogy with the
interpretation of Dirac's singleton as a shortened scalar in Anti de Sitter
spacetime.
