I finished Pauline's commission last night.
This model seems to be extremely popular as this is the 5th commission of this particular model, of course, all customised to the customer's specific needs. This one has a large front slip pocket and large zippered pocket at the back, both large enough to contain an iPad. Inside there is one large slip pocket, large enough to hold an A4 writing pad, as well as an elastic band to hold back a 0.5 liter water bottle. Outside there are pockets on each side to hold a mobile and/or glasses case. The lining is a sturdy linen fabric.
I think the shape of this bag is popular because it is light, large, can be used for work but is still stylish and not too businesslike but at the same time large enough to hold all you need. Also, privately, it is a great everyday bag and is also very useful for flying because it will hold everything you want to take with you in the cabin, weather you fly budget airlines or intercontinental. As it is made of fabric it is much lighter than leather, is sprayed outside and inside with a water repellant spray and is therefore easily spot cleaned.