Further work is planned at Norfolk County Council's headquarters - as part of a revamp which has already cost more than £70m.

Work on County Hall started in 2012, after its Conservative-controlled cabinet set aside £22m for structural repairs to the Martineau Lane building.

That work was triggered after masonry fell from the 1968-built council headquarters.

Barely a year after work started, £10m was added to the bill, as the true costs of what was needed emerged.

The scale of the work was subsequently extended to also cover County Hall's North Wing.

Further issues were identified around potentially dangerous defects, including a danger of "catastrophic failure", with a "very real risk of personal injury".

That all meant the total cost stood at more than £71.4m as of last summer.

And, now, the county council has lodged an application to its own planning committee for further changes.

The latest proposals include improving access to the North Wing, to bring the steps, lift and the changes in level in line with building regulations.

It would also see a pair of air conditioning units replaced with six cooling units and a new door added.

Documents lodged alongside the planning application by the council's consultants Purcell state: "The replacement of existing inefficient mechanical and electrical systems with new efficient systems will improve the environmental conditions of the internal spaces and are necessary as part of a larger refurbishment of the internal office spaces within the civic area."

The documents also state that the changes will prevent water from leaking through the pavement near the entrance into the boiler room below.

The documents do not state how much the latest work would cost and nobody at Norfolk County Council was available to confirm a figure - or if the work was already included in the previously announced £71.4m cost.

A decision on whether to grant permission will be made in due course.

When the original repairs were agreed, the demolition and rebuilding of County Hall was considered, but was ruled out.

As a Freedom Of Information Act request revealed earlier this year, that was despite a report which had recommended building a new headquarters.