Anzac Day parade Australia
A teenage boy from Blackburn has admitted plotting a terror attack at the Anzac Day parade in AustraliaGetty

A 15-year-old boy believed to be Britain's youngest ever terror suspect has admitted to inciting an Islamic State (Isis)-inspired terror attack in Australia.

The teenager from Blackburn pleaded guilty to inciting terrorism by encouraging the murder of police officers during the 100th Anzac Day ceremony in Australia.

Following his arrest, police said they believe the plot was inspired by the Jihadist terror group and involved using edged weapons against officers.

Prosecutor Paul Greaney said the boy sent thousands of messages to 18-year-old Australian suspect Sevdet Besim encouraging him "to commit an act of terrorism abroad, namely the murder of police officers during an attack upon a parade to commemorate Anzac Day in Melbourne".

In one message, the teenager suggested Besim "break into someone's house and get your first taste of beheading".

The boy, who cannot be named for legal reasons, entered the plea at London's Old Bailey via a video link from Manchester Crown Court.

A second charge of inciting terrorism overseas in relation to beheading a person in Australia was dropped by the prosecution.

The 15-year-old is to be sentenced on 3 September.

Anzac Day, held annually on 25 April, commemorates Australian and New Zealand soldiers killed during World War One and, more broadly, all wars, conflicts and peacekeeping missions.