A mechanical digger has begun tearing down the old St Peter Port School.
The Les Ozouets campus was built in the 1960s.
Specialist contractors have been removing asbestos, and now a mechanical digger is being used to break the building down.
The site should be levelled by mid-August, to allow a new Guernsey Institute to be constructed.
Institute Head Tracey McClean says the new campus will offer opportunity to many post 16 students:
"In three years time hopefully we will be moving into a brand-new building, so it will mean that we can increase our provision and opportunities on the island.
There's nothing like learning in the classroom and being with a group of peers and sharing ideas."

Muratti Tickets on now on sale
Tree protection order served on Guernsey landowner
Guernsey rejects inter-island ferry proposal
New housing development to support Guernsey residents with disabilities
Guernsey conservation group receive Royal recognition
Future of national newspaper distribution in Guernsey is uncertain
Guernsey's Elizabeth College to investigate allegations of historical abuse
Retiring Guernsey doctor auctioning artwork for Les Bourgs Hospice