Pictures from inside show the building in Old Road East still in good condition and seemingly free from vandalism.
Display boards, desks, chairs, filing cabinets and cooking equipment could be seen as if they had been emptied and left where they were when the school closed down.
There was also a picture of the site from 1992, while the board displaying the names of its house captains and head boy and girls was still intact.
Martin, who is known as DE-eVOLVED on YouTube, said: “It was great to finally explore the inside, which was still in very good condition and 99% free from graffiti.”
St Joseph’s Convent Preparatory School shut in 2021 due to issues with long-term finances and has sat empty ever since.
However, last year, property developers Galliard Ltd revealed proposals to convert the former Catholic school, near Echo Square, into six flats.
It also planned to demolish the outbuildings to build a three-storey medical centre, another apartment block of seven flats and 41 houses on the site.
The scheme was approved by Gravesham council in February, despite 113 objections from residents who raised concerns over privacy and parking.
Once built, it will include a variety of two and three-bedroom terraced houses, three-bedroom detached houses, and one and two-bedroom flats, each with an open plan kitchen, dining and living room.
While the doctor’s surgery, which will become the new home of Pelham Medical Practice, will have two waiting rooms, one interview room, 14 consulting rooms and six treatment rooms.
Speaking at the planning meeting, the practice manager, Jason Bowler, said a new surgery was needed to help the growing population.
Around 100 parking spaces have also been included for the entire scheme, as well as a park, landscaping, a new access for vehicles onto Old Road East and a pedestrian connection onto the site from Coombe Road.
Urban exploring is a hobby which involves venturing and usually documenting abandoned, derelict, or off-limits places, like historic buildings or tunnels, within a built environment.
It is not a criminal offence; however, it can breach civil laws, like trespassing, and in some cases can lead to criminal charges.
The experienced adventurers have previously filmed their exploration of the former Portland’s Factory Club and civil defence bunker underneath Kesson House, in Northfleet.
Martin added: “As always, we were respectful of the place we explored and stuck to the urban exploring code of take nothing but photos and videos and leave nothing but dusty footprints.”
