The Crown Prosecution service is appealing against a prison sentence given by a judge to a murderer from Swindon.
Minicab driver Chris Halliwell admitted killing Sian O'Callaghan in March last year.
A judge sentenced him to life in prison with a minimum tariff of 25 years. The CPS believes that is too lenient.
The CPS appealed to Attorney General Dominic Grieve MP under the Unduly Lenient Sentence Scheme. He in turn referred the sentence to the Court of Appeal. If the court agrees with the Attorney General, Halliwell's tariff will be increased.