The Attorney General's Office is considering whether to appeal against what has been called the "unduly lenient" sentence of four years and eight months for a man who choked a woman to death during sex.
Sam Pybus, 32, was handed the sentence for the manslaughter of Sophie Moss, a 33-year-old mother-of-two, at Teesside Crown Court on Tuesday.
The court heard how Pybus was drunk when he applied pressure to her neck for tens of seconds or even minutes in February.
He later woke up at her flat in Darlington to find her naked and unresponsive, did not dial 999 but waited in his car for 15 minutes before driving to a police station to raise the alarm, the court heard.
He had applied enough pressure to her neck for long enough to kill, a post-mortem examination revealed. There was no evidence of other injuries or violence.
On Tuesday the Crown Prosecution Service said there was insufficient evidence to support a charge of murder, as there was nothing to suggest Pybus intended to kill Ms Moss or cause serious harm.
Pybus, who is married, told police they had been in a casual relationship for three years and that she encouraged him to strangle her during consensual sex.
The court heard her long-term partner, who was not named in court, said something similar.
Judge Paul Watson QC sentenced Pybus to jail for four years and eight months, having reduced his sentence from seven years for his early guilty plea to manslaughter.
Now, Labour's Harriet Harman, chair of parliament's Joint Committee on Human Rights, has written to Attorney General Michael Ellis QC to complain about the "unduly lenient" sentence and encourage him to apply for the Court of Appeal under the Unduly Lenient Sentence scheme.
She said: "This sentence fails to reflect the gravity of the crime, the impact of her death on her family including her two young children, his sole culpability for her death, his cynical shifting of the responsibility from himself to her and sends out the message that killing your girlfriend during sex is a minor matter."
A spokesperson for the Attorney General's Office said: "We have received a request for the case of Sam Pybus to be considered under the Unduly Lenient Sentence scheme.
"Only one request is required for us to review whether a sentence is too low.
"The Law Officers have 28 days from sentencing to consider the case and make a decision on whether to refer the sentence to the Court of Appeal."