R (On the Application of British Pregnancy Advisory Service) v Secretary of State for Health and Social Care [2019] EWHC 1397 (Admin) 

This article originally appeared in Issue 2 (July 2019).

The court considered the meaning of the phrase “the pregnancy has not exceeded its twenty-fourth week” in section 1(1)(a) of the Abortion Act 1967 and concluded that a woman would have exceeded her 24th week of pregnancy from midnight on the expiration of her 24th week. 


Section 1(1) of the Abortion Act 1967 provides, in summary, that a doctor will not be guilty of an offence if he/she terminates a pregnancy in certain defined circumstances. The first circumstance (in section 1(1)(a)) is that “the pregnancy has not exceeded its twenty-fourth week”. 

On 23 July 2018 the Chief Medical Officer wrote to all doctors explaining that the Department of Health and Social Care’s interpretation of that phrase, based on legal advice, meant that all parts of the abortion procedure had to be completed within the completion of 23 weeks and 6 days. The Claimant British Pregnancy Advisory Service challenged that “decision” (imputed to the Secretary of State) in judicial review proceedings, arguing that it represented a change to long-standing practice with the effect of shortening the lawful period for an abortion under the provision by one day. 

The parties’ positions 

It is helpful to quote from the judgment of Mr Justice Supperstone at [33] to [34] to reiterate the parties’ positions: 

“The Claimant’s case is that a pregnancy does not exceed 24 weeks on the day that it reaches 24 completed weeks, but on the day after that. Week 24 plus 0 is the day that a pregnancy has reached the end of its twenty-fourth week, but not exceeded it. A pregnancy does not exceed its twenty-fourth week until it has reached week 24 + 1 day. 

The Secretary of State’s case is that the 24th week is reached when the 23rd week ends, at the end of week 22 + 6, and runs from week 23 + 0 to week 23 + 6. After that it is exceeded. The Secretary of State accepts that his previous interpretation was wrong.” 


Mr Justice Supperstone agreed with the Secretary of State, holding that the natural meaning of “exceed” in the section had the effect that pregnancy “exceeded” 24 weeks from midnight on the expiration of the 24th week from the first day of the last menstrual period. This meant at the end of 23 weeks + 6 days. He explained his reasoning by reference to the way we describe someone’s age: their life begins on the day they were born, but they are not considered to be one day old until the expiry of the first day, and likewise we do not refer to someone as one year old until the expiry of their first year. Similarly, when someone is 23 weeks old, they have in fact entered their 24th week. The first day of that week is day 0, and at the end of day 6, the period has expired. 

In the absence of some clear indication of a contrary parliamentary intention, the court said that natural meaning should be given effect. Further, it rejected an argument that the advice posited an interpretation contrary to how the phrase had been understood by all properly informed parties since its enactment. Supperstone J said that Parliament had not approved or enacted any measure that indicated it took a particular view of the interpretation of the words concerned, over any period, let alone a long period. The evidence did 

not indicate a settled construction of practice in line with the Claimant’s proposed construction. Accordingly, the decision handed down by the Chief Medical Officer was lawful. 

Aside from setting out some principles of construction in relation to time periods, which might have some general application, this is clearly a very specific decision of statutory construction. The decision makes for enjoyable (if slightly esoteric) reading, however, and it is worth including the following passage from the Chief Medical Officer’s decision letter, if only to count the number of times it must be read in order to make sense! 

“This advice is based on the fact that, clinically, a pregnancy is dated from the 1st day of the woman’s last menstrual period (LMP). As you will be aware, this day is counted as day 0 of her pregnancy. Therefore, when the woman reaches 23 weeks + 0 days she will have entered her 24th week of pregnancy, which will run from 23 weeks + 0 days to 23 weeks + 6 days (7 completed days of pregnancy in total). Using this method of calculation, a woman will have exceeded her twenty-fourth week of pregnancy once she is 24 weeks + 0 days pregnant, or in other words, from midnight on the expiration of her 24th week of pregnancy. On the expiration of her 24th week of pregnancy, she will have been pregnant for a total of 168 days; an abortion on the 169th day (24 weeks + 0) would, in the view of DHSC’s legal services, be unlawful.”