The BBC says "Banksy works cost public almost £150k" because "The Ministry of Justice (MoJ) says it has spent £50,000 trying to remove paint from the wall of the Grade II-listed building in Carey Street."

Therefore, the title is incorrect. The cost to the public is much more than £150k. The Ministry's damage to this freely-contributed artwork has probably already cost the public a few million £, not just £150k

[0] https://www.dawsonsauctions.co.uk/news-item/how-much-is-an-o...

It seems like someone doesn't get the symbolism of the Banksy piece.

how much does graffiti cost the public in general?

And then, further down in the article, the picture of a whole structure built to block the view of the piece, with a locked door. Satire writing itself!

If they're so concerned about cost, why not do what you'd do with any other vandal with a spray paint can...

Immediately paint over it with grey paint to neutralize the "blight", then efficiently do a deeper clean / removal / repair the facade.

Seems like they gave the Banksy very special treatment of fence, guards, etc. and now are paying for the side effects of that.