Formal:
* En route pour l'Angleterre: This is the most literal translation and is appropriate in formal settings.
* Je pars pour l'Angleterre: This means "I'm leaving for England" and is also quite formal.
Informal:
* Je m'en vais en Angleterre: This means "I'm going to England" and is more informal.
* En Angleterre, on y va! This translates to "To England, we go!" and is very casual.
For someone else:
* Il/Elle part pour l'Angleterre: This means "He/She is leaving for England."
The best option will depend on the specific context and your relationship with the person you are speaking to.