National teams are supposed to represent the best a country can produce domestically.
In sports such as football, the decisions a manager makes can be crucial in deciding the outcome of a match, and ultimately a tournament, such as deciding when to make key substitutions, which players to field, and control of training. As such, they can be viewed as a vital member of the team, alongside coaches and players alike.
In this regard, a team that is managed by a foreigner cannot be said to represent the ability of a single country only, and so the manager of any national team should always be drawn from that nation.
Whether or not something is acceptable by the rules doesn’t mean that we as a nation cannot make certain self-imposed criteria. We can choose, as a matter of national pride, to give the job to an Englishman.

If the goal is to make the England team the best it can possibly be and bring some success to England then the person in charge should be the best man for the job, regardless of nationality.

Ther manager should be foreign because all english managers are so crap!