From the official website of The British Monarchy:
The following message was sent by The Queen to the Emperor of Japan:
I was saddened to hear of the tragic loss of life caused by the earthquake which has struck North East Japan today. Prince Philip joins me in extending our heartfelt sympathy to Your Majesty and the people of Japan. Our prayers and thoughts are with everyone who has been affected by the dreadful disaster.
Her Majesty Queen Elizabeth, Emperor Akihito and Empress Michiko, Prince Philip in London, 2007