Martha operates her own business providing childcare and nannying services. Martha was looking after three children: Harry, Island and Jan. Martha has a large garden and the children were playing football. While they were busy playing, Martha took a phone call.

While Martha was distracted on the phone, Harry kicked the ball over the fence bordering the garden. When she told Martha, Martha distractedly said "Go and get it then!". Despite the fence being old and rotten, Harry tried to climb over it but the fence collapsed under her weight and Harry broke his arm and both his legs in the fall.

What tort liability might Martha be liable for any why?