What is the ruling on working in the field of teaching Islamic Sharia at an Islamic center in London, knowing that I am a widow with a child and need to travel alone for this job?

We advise you not to reside in non-Muslim lands if you are able to reside in a Muslim country, especially since you are a widow with children. Your stay there poses a danger to your religion and morals.

However, if necessity compels you to stay, then there is no harm in you performing the aforementioned work, even if you go there alone, because moving within cities is not considered travel. But be wary of being alone with non-mahram men or mixing with them. You must be veiled with the شرعي (Shari'i) hijab, modest, and adhere to the etiquettes of Islam.