I had an interesting experience with my BIL and his twin girls both toddlers one summer's day at MIL's house where there was a small pond about 8 ft by 3 ft by 2-3 ft deep.
MIL had decided to serve a picnic style lunch in the garden so we all sat down to eat, me, my DH, BIL, SIL, MIL and 2 toddlers. After a few minutes the girls were up and running towards the pond and I was the first adult up on my feet in quick pursuit. I grabbed them before they reached the concrete flagstones which edged the pool. I sat them down to eat lunch again and returned to my seat. Yes within a couple of minutes I ran after them again and grabbed them before they reached the pond. As I returned to my seat my BIL said "Don't worry about the pond, the girls have to learn about water sometime." I just replied "Well that's fine if you want to spend the afternoon at A and E at the hospital."
PS my SIL phoned after we had left. She was washing up and MIL and BIL were talking standing at the edge of the pond. The girls were running round the garden and ran up beside their father, stopped, and the eldest one stepped straight into the water. Did she scream!!
I have just given up with my BIL and SIL.....it makes life easier.
Estranged Son and Future Granddaughter
To think that London, or anywhere else for that matter, does not belong to any one demographic