Here's a few quotes from an ex met detective that pretty much describe it. And I stand by what I said, whether I am misquoted or not.
“The question is do you treat it like a crime scene that needs to be preserved right from the start or is the most likely explanation that she wandered off? The Portuguese police were widely criticised for not sealing off the scene, making it a crime scene.
“But if there is a chance the missing girl could be wandering around lost in the immediate area, then that rightly takes priority. You are prioritising searching the immediate area rather than sealing off the scene.“If there is sign of a violent struggle or forced entry then it would be different, but that wasn’t the case with Madeleine’s disappearance.
“If there was sign of forced entry, then your thinking starts going down the line of crime rather than just a missing person. But in the absence of any evidence your natural thought is she has wandered off.“You think, ‘Let’s start looking for her’, rather than thinking of anything as sinister as abduction.“That would have been the call for the uniformed officers who were first on the scene at the Ocean Club.
“Once she was not found in the immediate area then I would have asked the officers to look for evidence of a crime.
“I can well imagine that the Portuguese police’s initial thoughts were that they were going to find the little girl wandering around in her pyjamas no further than half a mile from the apartment.“When the searches have proved fruitless I would want to talk to the parents.
“Very quickly there should have been the realisation that this was a crime rather than something more innocent. That should have been realised within 30 minutes, but in Madeleine’s case it clearly wasn’t realised all that quickly."https://www.mirror.co.uk/news/uk-news/6-errors-madeleine-mccann-detectives-10272590