We share a courtyard with a company behind us and they are looking to build a fence to mask our air conditioning units. Our fire escape opens into this courtyard and they want to include a hinged gate to allow us access into the courtyard.

My opinion is that this is illegal and that we should have immediate access into this area and not have to open an adjacency gate as a means of escape

Am I  right ?

Ladbros

As long as it has a simple fastening not requiring a key or code and opens in the direction of escape (ideally) it's not necessarily prohibited. I'd check to see what consent they need to build on a shared courtyard - who owns it, what rights are in leases, etc.