Mr Smith, who represented the mother in the trial at Nottingham Crown Court earlier this year, said her sentence was too long.
Judge Philip Robey said he took this into account when passing sentence, but warned harsher penalties would be given out for similar offences in future.
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Passing sentence, Sheriff Andrew Normand said there was "no other method of dealing with this" than by a custodial sentence.
"Essentially, this was a death sentence, " said Dr. John Harold, a Los Angeles heart specialist who is president of the College of Cardiology.
Jerry Richardson, who was her right-hand man during the thuggish days when she surrounded herself with a gang known as the Mandela United Football Club, and is currently serving a life sentence for Stompie's murder, said this week that she ordered that the boy be killed, but did not herself stab him.
"This is a death sentence for Maikel because he said if he weren't released on 4 October he'd refuse water, " he told the BBC.
"This sentence is a clear message to those who commit crimes, " she said.
The Crown Prosecution Service said a public order charge would be more appropriate but as this does not carry a custodial sentence it would not be in the public interest to proceed.
"The tragedy of this crime is that it's a story of betrayal, " Judge Cleland said before handing down the sentence in Centre County Court.
He said India wanted Headley tried here and that he would have possibly got a "serious and severe" sentence in this country.
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"Clearly, at some stage we will look for his return to the United Kingdom, so he can serve the sentence for the fraud offences for which he has been convicted in this country, " a spokesman said.
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