I think it's fair to be open minded that I could be anybody, pretending to be a social worker. I respect your view and am not responding to challenge that. I also do not usually post on here however find it useful to develop my understanding of different perspectives in relation to parenting. I am also on leave right now so having a scroll and some extra time on my hands.
As many people have mentioned, all 8 year olds are different due to numerous factors, and of course parental judgement of their child will lead decision making in these situations which is why the law on leaving children at home alone is ambiguous. I mention the law regarding criminal responsibility as it provided some context regarding the expected legal age in which children can be held accountable for harming others which is 10 and over and this child was 8.
My point was, if you put personal views and experiences aside, regardless of parental judgement, if a serious accident happens to a child, in the UK, the responsibility will always fall on the adult who was supposed to be supervising the child and made the judgement that it was safe to leave them alone.
Here is a very useful quiz on the NSPCC website to help parents to determine if it's safe to leave a child alone if they feel unsure:
www.nspcc.org.uk/keeping-children-safe/in-the-home/home-alone/home-alone-quiz/?_ga=1.93651739.740386347.1433258561
A 16 month old child is at the prime age for having accidents as they explore the world, become steady on their feet and lack any understanding of danger awareness. This only lasts for a couple of years so as much as it is full on, it won't be forever.
I have worked with a number of great parents (similar age group of children who have sustained significant injuries) and have seriously regretted making similar decisions as mentioned in this post, not due to intentional neglect but a lack of consideration of the consequences. Lots of parents are not exposed to the variety of accidents that children of this age can experience unless it has happened to them, somebody that they know or work in a front line services.
If there is a main carer, who is looking after two children most of the time then they will work out a way of doing basic things like going to the toilet and having a quick shower whilst the children are in ear shot ect as part of the daily routine as that is a part of parenting, and accidents cannot always be avoided and are a part of life. However in this situation, if anything did happen to the child, would the Dad have heard the children over the noise of the lawn mower and would he be able to justify that the decision to leave them alone was necessary and proportionate if anything happened.
That will be my final message but I just wanted to share some insight that I thought may be helpful, and possibly save some avoidable accidents toward young children in the future based on my experiences in my role, and hindsight that parents in real situations wish that they had known sooner. You rarely hear about these situations in the media.