Q:  When will the embassy be opening a book of remembrance for Prince Philip (in the same way that books were opened at all British missions on the death of Diana, Princess of Wales?)

Please refer to the embassy website. I expect that the embassy will comply with the  Official Guidance 

 https://www.gov.uk/government/publications/guidance-for-the-period-of-national-mourning/guidance-for-the-period-of-national-mourning

 

Books of Condolence

A Book of Condolence is available online at the Royal Website. Unfortunately, in order to comply with COVID-19 restrictions in place, and to reduce the risk of transmission, Books of Condolence will not be available in public buildings for people to sign in person.

 

As per the Royal website;

During the current public health situation, Books of Condolence will not be available for the public to sign.  Members of the public wishing to express their condolences are encouraged to send a message to the Royal Family via the online Book of Condolence on this website.