I don't understand the bold text in the OATPA 1861.
How is s. 18 "in at least one respect, broader than section 20"?
Are there more respects than just "one respect"? How many exactly? What are they?
Herring, Criminal Law: Text, Cases, and Materials (8 edn, 2018). p. 372.
offence under section 47 because it may not be easy to demonstrate that there was a battery or an assault?251 Although the Law Commission252 and many commentators are convinced by these arguments there are a few commentators who are willing to stand up for the Offences Against the Person Act 1861. One of the strongest defences of the Act is provided by John Gardner. In the following extract, he replies to some of the objections mentioned previously. He starts by challenging the claim that the Act is irrational:
J. Gardner, ‘Rationality and the Rule of Law in Offences against the Person’ (1994) 53 Cambridge Law Journal 502 at 503–11
The rationality argument figures less prominently in the Law Commission’s latest report than it does in the consultation paper which preceded it. One can only speculate as to the causes of its demotion, but its spirit certainly lives on in the draft Bill. The spirit of the argument is captured in the Commission’s comment that ‘sections 18, 20 and 47 of the 1861 Act . . . were not drafted with a view to setting out the various offences with which they deal in a logical or graded manner’. The assumption is that the three offences can, in substance, be graded, and that this would be the logical way to define and organise them. Between them they deal with matters which would most naturally be dealt with in a hierarchy of more and less serious offences all conforming to a standard definitional pattern. The irrationality of the 1861 Act lies in its failure to take this natural path, its failure to carry the underlying hierarchy of seriousness over into the actual definition and organisation of the offences. Thus, section 18 should be regarded, in substance, as an aggravated version of section 20; and yet there are miscellaneous differences between the two sections which do not appear to bear any rational relation to the aggravation. Likewise, section 20 should be regarded, in substance, as the more serious cousin of section 47; and yet the two offences are drafted in quite different terms, so that the essential difference in point of seriousness is obscured by a mass of other, utterly irrelevant differences. If the sections were properly graded in definition as they are in substance, then section 18 would surely cover a narrower class of cases than section 20 which would cover a narrower class of cases than section 47; and yet section 47 is, in at least one respect, the narrowest offence of the three, while section 18 is, in at least one respect, broader than section 20. That is surely irrational. The law on such matters should be thoroughly governed, in the Law Commission’s words, ‘by clear distinctions . . . between serious and less serious cases’. That a section 18 offence should be regarded, in substance, as a more serious version of a section 20 offence is easy enough to understand. Section 20 covers malicious wounding and the malicious infliction of grievous bodily harm. Section 18 covers malicious wounding and maliciously causing grievous bodily harm, when these things are done with intention to do grievous bodily harm or to prevent or resist arrest. The extra element of intention required for a section 18 offence obviously accounts for the difference between the sentencing maxima (five years’ imprisonment under section 20 and life under section 18), and marks a difference in point of seriousness (or potential seriousness) which the Law Commission is rightly anxious to retain in its hierarchy of replacement offences. The Commission has not even felt the need to explain its decision, however, to eliminate the difference in the causal elements of sections 18 and 20. Section 20 requires that grievous bodily harm be inflicted,
251 In fact, in the light of DPP v K  1 All ER 331 there is likely to be a battery.
252 Law Commission (2014).