  We consider a minimal classically scale-invariant extension of the Standard
Model. In this theory, the Higgs mechanism is triggered and the electroweak
symmetry breaking is generated radiatively by the Coleman-Weinberg sector which
is coupled to the SM Higgs. We extend the Higgs portal interactions of the
theory to include an additional singlet which is also non-minimally coupled to
gravity. This generates a single-field slow-roll inflation mechanism in the
effective field theory formulation which is robust up to Planck scales. Our
approach does not require integrating in any additional new physics degrees of
freedom to unitarise the theory in the sub-Planckian regime where inflation
happens. As a result, no large threshold corrections appear in our approach to
inflation so that the electroweak scale and the SM Higgs mass are not affected.
The singlet field responsible for inflation also gives a viable dark matter
candidate in our model. We also discuss the relation between classical
scale-invariance of the effective theory and the possible local scale
invariance of the full theory and comment on the naturalness of the electroweak
scale.
