I will go to France from 17/12/13 – 19/12/13, then I will come back to London. And again I will go back to Portugal and Spain from 26/12/13 to 03/01/14 which I will stay in Spain for the longest period. However, the Spanish consulate told me that I have to request for the visa from the French consulate.

The point is: Do I need to apply for a visa for a single trip two times (from French and Spanish consulate) or a single visa for multiple time (from French consulate).