So soon as may be after the local housing authority have declared an area to be a clearance area, they shall proceed to secure the clearance of the area (subject to and in accordance with the provisons of this Part) by purchasing the land comprised in the area and themselves undertaking, or otherwise securing, the demolition of the buildings on the land.
Where the authority determine to purchase land comprised in a clearance area, they may also purchase—
Where the authority have determined to purchase land under this section, they may purchase the land by agreement or be authorised by the Secretary of State to purchase the land compulsorily.
The powers conferred by subsection (3) are exercisable notwithstanding that any of the buildings within the area have been demolished since the area was declared to be a clearance area.