Dickens probably wrote the following portions of 'The Metropolitan Protectives': from 'There are six hundred' (p. 100) to 'do nothing' (p. 101); from 'We fall into a doze' (p. 101) to 'in the morning' (p. 103); from 'We have not' (p. 104) to 'the Bill of Rights?' (p. 105); from 'Believe us' (p. 105) to the conclusion.
Dickens may also have added to the following sections: from the opening to 'no such distrust' (p. 97); from 'No other door' to 'with defiance' (p. 99); from 'O! Please sir' (p. 103) to 'very source of crime' (p. 104).
In addition, Dickens seems to have gone over other sections of the essay with great care and to have made many emendations. For a discussion of the Dickens-Wills attributions, see note to 'Valentine's Day at the Post-Office.'
Dickens set forth his original idea for 'The Metropolitan Protectives' in a letter to Wills (3 April 1851):

I thought of something for to-night, that I think will make a splendid paper ... This is it; A Night in a Station-House. If you would go down to our friend Mr. Yardley, at Scotland Yard, and get a letter or order to the acting chief authority at that station-house in Bow Street, to enable us to hear the charges, observe the internal economy of the station-house all night, go round to the cells with the visiting policeman, etc., I would stay there, say from twelve to-night to four or five in the morning. We might have a 'night-cap,' a fire, and some tea at the office hard by. If you could conveniently borrow an hour or two from the night we could both go. If not, I would go alone. It would make a wonderful good paper at a most appropriate time, when the back slums of London are going to be invaded by all sorts of strangers.
You needn't exactly say that I was going in propria (unless it were necessary), and, of course, you wouldn't say that I propose to-night, because I am so worn by the sad arrangements in which I am engaged, and by what led to them, that I cannot take my natural rest [his father had died on 31 March]. But to-morrow night we go to the gas-works. I might not be so disposed for this station-house observation as I shall be to-night for a long time, and I see a most singular and admirable chance for us in the descriptive way, not to be lost.
Therefore, if you will arrange the thing before I come down [to the Household Words office] at four this afternoon, any of the Scotland Yard people will do it, I should think; if our friend by any accident should not be there, I will go into it.
If they should recommend any other station house as better for the purpose, or would think it better for us to go to more than one under the guidance of some trustworthy man, of course we will pay any man and do as they recommend. But I think one topping station-house would be best.

In a letter to Wills dated 13 April 1851, Dickens writes: 'I enclose you the Police Article. I have cut down the number of cases, to save tediousness. Two drunken men, for example, could scarcely have been done with. It occurs to me that I have not described the cells. But I had better 'put in that,' and any other line or so that occurs to me, when I get the proof. For the present slips [pages of manuscript] are horribly mauled. I have done all I could - sat at it nine hours without stirring - and hope it will come out well.'
Though the immediate object of 'The Metropolitan Protectives' was to assure a nervous middle class that it would be well protected during the forthcoming Great Exhibition, Dickens' larger interest in the matter transcended the topical. Crime detection, police courts, law enforcement, and similar subjects always fascinated him. He wrote several articles for Household Words on such topics, and he often included similar materials in his novels.

Harry Stone; © Bloomington and Indiana University Press, 1968. DJO gratefully acknowledges permission to reproduce this material.