Three members of staff - Celia Diston, who was the daily supervisor, Sharon Hibberd, Elizabeth Cheney, and parent helper Angela Doherty - were looking after the 14 pupils attending the playgroup on the day of Abby's death.
At about 10am, the children were told to tidy up by putting their ride-on toys in a shed outside the back of the building.
Mrs Cheney was in the store taking the toys while Mrs Doherty watched the children from the door.
Mrs Doherty helped Abby, the last in the group, to put her toy away and then shepherded her in to join the other children. Her attention then became distracted by another child who was crying and she attended to him.
Mrs Cheney, after stacking the toys, returned to the building and shut the back door. By this time, Abby was thought to have escaped through the back yard and open side gate that was normally bolted, through the car park and into the neighbour's garden.
An Ofsted inspection in July 2002 had recommended that a risk assessment needed to be conducted, although it found security had been good at the pre-school club. Policy had been changed so the side gate was not used for access by parents and pupils.
Janette Atkins, chair of trustees of the charitable trust that ran the nursery, told the inquiry staff were responsible for carrying out safety checks and that it was policy to check the back gate only when children were playing outside - a point also made by all members of staff on duty that day.
However, Sheila Flanders, who inspected the playgroup for Ofsted, told the inquiry she would expect some checking procedure on the outside of the building, even though "children were not playing out".
The playgroup closed on the day of the incident and is no longer a registered charity.
Neither the Crown Prosecution Service nor the Health and Safety Executive sought to prosecute in relation to the matter.
However investigating officer Detective Inspector George Stepney, of Warwickshire Police, told the inquiry he believed the death was preventable had safer working practices and effective management been in place and up to date.