A teenager caused £30,000 of damage during a seven-hour rooftop siege with police.

The boy, then aged 15, was being held at Rossie Secure Unit in Montrose, Angus, when he and another boy sparked a standoff that led to almost 30 police officers being called to the scene.

During the incident they stripped an area of roof clean of tiles and used them to cause thousands of pounds worth of damage to police cars and staff vehicles.

Dundee Sheriff Court heard the day before the attack the boy had been told he would be leaving the unit on his 16th birthday due to his "aggressive and violent" behaviour.

He then told his family he was "upping the ante" in a bid to get a jail sentence.

Police were later called after he made threats to staff, resulting in him punching an officer who attended.

The following day another teenager, who was previously prosecuted over the incident, robbed a staff member at the unit of her access pass for the building and used it to release the accused from his locked room at 4.30pm on February 8.

Both boys threw slates and other debris at vehicles in the car park.

It resulted in two police vehicles as well as other cars belonging to staff being damaged.

The 16-year-old, of Lanarkshire, pleaded guilty on indictment to charges of assaulting police constable Mark Garnes on February 7 and culpable and reckless conduct committed on February 8.

Both incidents occurred at Rossie Young People's Trust.

Sheriff Alastair Carmichael deferred sentence until January next year and continued the teenager's bail meantime.

The court heard that since the incident the boy has been jailed for a total of 22 months over a string of incidents and faces sentencing in January at Lanark Sheriff Court over a gun robbery.