What is 'take you for a policeman'?
But there was no need to announce him. Miss Fitch was in the hall as Liz ran up the steps, and she said in tones more surprised than grieved:
'Liz, you are five minutes late!' Then she saw the Inspector, and said: 'Well, well, they were right. They said that no one would ever take you for a policeman. Come in, Inspector. I have wanted so much to meet you. Officially, as it were. Our last encounter could hardly be termed a meeting, could it. Come into the morning-room. That is where I work.'
(Chapter 11 To Love and Be Wise) Miss Fitch is a famouse novelist who is waiting for Liz, her secretary, to begin her dicatation. Liz was with the Inspector, who is asked to investigate the missing case of Leslie Searle, who was a visitor of Miss Fitch. I think 'take you for a policeman' means that 'regard Liz as a policeman'. Am I right? If so, why did the speaker say so?Sorry, I think I've got the phrase incorrectly. The speaker should imply that the Inspector does not look like a policeman. Am I right?

Question

What is 'take you for a policeman'?
But there was no need to announce him. Miss Fitch was in the hall as Liz ran up the steps, and she said in tones more surprised than grieved:
'Liz, you are five minutes late!' Then she saw the Inspector, and said: 'Well, well, they were right. They said that no one would ever take you for a policeman. Come in, Inspector. I have wanted so much to meet you. Officially, as it were. Our last encounter could hardly be termed a meeting, could it. Come into the morning-room. That is where I work.'
(Chapter 11 To Love and Be Wise) Miss Fitch is a famouse novelist who is waiting for Liz, her secretary, to begin her dicatation. Liz was with the Inspector, who is asked to investigate the missing case of Leslie Searle, who was a visitor of Miss Fitch. I think 'take you for a policeman' means that 'regard Liz as a policeman'. Am I right? If so, why did the speaker say so?Sorry, I think I've got the phrase incorrectly. The speaker should imply that the Inspector does not look like a policeman. Am I right?

Answer

"I never took you for a police man", means: "I never thought that you could be a police man" or "I never expected you to be a policeman" or "I never knew you were a policeman (by looking at you / by knowing you)"

You can say "I never regarded you as a policeman". It is basically the same, but it may sound a bit different as it is not used much in negative terms "Never regarded", but it can still be used.

Answer

It means no one would think that he looked like a policeman.