Is the marriage of a Muslim woman to an English man who converted to Islam but does not adhere to its teachings permissible or forbidden?

If a disbeliever utters the two declarations of faith (Shahadatayn), it is either as a statement of information or as a commitment to Islam. Uttering the Shahadah merely as a statement of information does not benefit the utterer, because it is simply a declaration and does not establish for him the ruling of Islam. Many People of the Book and polytheists testified to the prophethood of the Messenger, peace and blessings of Allah be upon him, but they did not follow him, so this testimony did not benefit them. Islam is not merely knowledge and acknowledgment; rather, it is knowledge, acknowledgment, submission, and commitment to obedience, both outwardly and inwardly. So, whoever says, "I know that he is a prophet, but I will not follow him nor embrace his religion," is among the most disbelieving of disbelievers.

Accordingly, marriage between a Muslim woman and a disbelieving man who has not committed to the rulings of Islam is null and void. The woman must separate from him immediately and not allow him access to her, as there is a consensus among Muslims on the invalidity of a Muslim woman's marriage to a disbeliever.