Martha operates her own business providing childcare and nannying services. Martha was looking after three children: Harry, Island and Jan. Martha rushed to give first aid to Harry, but this meant Island and Jan were left unsupervised. They left the garden where a fence had collapsed and ended up in the next door property, where building works were currently going on. While exploring the building site, Island turned on a power tool which she then left unattended.

Jan climbed onto some scaffolding and suffered severe cuts to his leg from a piece of sharp metal. Jan also suffered from a form of blood poisoning which made him very ill and extended his hospital stay. When Martha was at the hospital visiting Jan, Jan's doctor told her "I'm not sure the blood poisoning was your fault".

The power tool Island left on started a fire which caused 20,000 worth of damage at the building site.

What tort liability will Martha be liable for on Island and Jan, and the fire of the building, and why?