Emlyn Jones said that while the boy was in hospital, a “wider picture of long-standing physical abuse emerged”, including the discovery of multiple fractured ribs, fractured legs and a fractured sternum suffered across several incidents before the fatal attack.
He also said that while it could not be ascertained whether Klevi Pirjani or Nivalda Pirjani inflicted the fatal violence, “whichever it was, they did so with the encouragement of their partner”.
Sentencing them in March, Mr Justice Andrew Baker said the pair were “in this together, encouraging each other” to attack their “defenceless” son.
He said that who “fatally battered” the infant “remains the guilty secret of a warped relationship, in which you came first for each other to an unnatural degree”.
Rupert Bowers KC, for Nivalda Pirjani, acknowledged in court that “of course” her sentence was lenient, but that the sentencing judge “considered all of the factors”.
He said: “There is nothing that would indicate that the sentences he passed are beyond the ambit of reasonableness, or an error of principle, so that this court should interfere with his exercise of discretion, having heard all the evidence.”
Sarah Vine KC, for Klevi Pirjani, also said her client’s sentence was “undoubtedly lenient, but not unduly, and leniency in itself is not a vice”.
Klevi and Nivalda Pirjani, watching proceedings from HMP Wakefield in Yorkshire and HMP Styal in Cheshire respectively, showed no reaction as their sentences were increased.