I went to the door and shouted her - simultaneously shaking her treat jar at the door - that particular method always brings the desired result in about three nano seconds - but it, too failed. Two minutes later the 'phone rang. It was the nearby Garden Centre (well actually it was a staff member from the Garden Centre - obviously not the actual Garden Centre - that would be impossible) to tell me that they had Millie! Thank goodness that she has a phone number on her collar tag. Apparently she was spotted by a passing motorist wandering by the side of Seven Hills Road (very busy - very fast road). When I got there to collect her she was enjoying the undivided attention of four staff members who were all making a huge fuss of her. She looked at me as if to say 'I'm having fun - don't even think about taking me home' - a bit like men do when they're enjoying a party and you want to get home because the babysitter needed to be taken home two hours ago - you know the look!
The staff then proceeded to tell me that Fifi (killer cat) is a regular visitor there too!!! She pops round most days!!! Obviously Millie must have followed Fifi - who will know all the escape routes through the garden fencing.
I'm going to have to keep a closer on eye on her from now on.