Hi there hope i can be of assistance.
Ok the ESp stands for electronic stability program. This is intergrated in to the ABS system.
The usual cause is a damaged ABS sensor or local wiring in the wheel arch.
However, the best way to confirm the fault is with a diagnostics scan. This dosent have to be done by Ford.
But if you car is still under warranty, ABS sensor faults are covered in 3rd year warranty.