The action was approved during a meeting of the planning committee on Thursday (December 16) and, if it goes ahead, could see the landowner facing a fine of up to £20,000.
At the centre of the proposed prosecution is 145 High Street, in Hurstpierpoint, which lies in a Conservation Area.
In 2017, the council gave permission for substantial ground and first-floor extensions to be added to the building, while imposing three conditions relating to its design and finish.
But councillors were told that, when the work started, it was considered to be ‘materially different’ to what had been approved.
As such, the work did not have planning permission and represented a breach of planning control.
Applications to remedy the problem were submitted later in 2017 and in 2018 but both were refused.
The council then issued an enforcement notice calling on the landowner to remove the unauthorised work – a notice the landowner appealed, only to be refused again.
The deadline for complying with the enforcement notice was March 17 2020 but dealing with it was set aside during the pandemic.
The committee was told that the owner intends to carry out the necessary work in the new year, which could see the council decide not to prosecute.
Rodney Jackson (Lib Dem, Hurstpierpoint & Downs) told the meeting: “When the original planning permission was given, it was acceptable.
“But this is in a Conservation Area and it therefore needed to conserve the character of that part of the High Street – not the modern sort of building you see in front of you.”
Clive Laband was more blunt, calling the work ‘an abomination’ which ‘seeks to undermine’ the planning process.
Mr Jackson also said the concrete rendering on the front of the building had ‘come forward several inches into the footway’ making that part of the pavement very narrow.
But images on Google Maps show that that had also been the case with the original building.