The sentencing of a British teenager accused of plotting an Anzac Day terror attack in Melbourne has begun.

The 15-year-old schoolboy is due to be sentenced after he pleaded guilty to encouraging the murder of Australian police officers in Melbourne.

Police allege he advocated for a terror attack, to be carried out in the name of ISIL, against police officers as they marched in this year’s Anzac Day parade.

The sentencing will take place in Manchester Crown Court. (9NEWS)

He pleaded guilty in July to inciting terrorism overseas.

Justice John Saunders has set aside two days to sentence the teen in in the Manchester Crown Court.