When to apply for British Citizenship (BC)

Dear all,

I have a friend would like to know when his wife would be eligible to apply for BC- Does she apply for BC counting from the date of marriage or the date she entered the UK?

1- He is British.

2- Got married in Algeria November 2007.

3- His wife came to UK in March 2008.

4- His wife received ILR this October 2010.




Thank you

March 2011.