Our deepest condolences, thoughts and prayers go out to Her Majesty the Queen and the whole royal family at the loss of a much loved husband, father, grandfather and great grandfather. There is an online book of condolence available for signature here and the Church of England has issued the following prayer which you may also find helpful.
God of our lives,
we give thanks for the life of Prince Philip,
for his love of our country,
and for his devotion to duty.
We entrust him now to your love and mercy,
through our Redeemer Jesus Christ.