From a comment on Facebook
"Islam protects the rights of people of other religions to practice their religion, and apply punishments based on their belief system.

"For example, when the community of Jews in Madinah were deciding how to punish a man who had committed adultery and consulted the Prophet (saws), the Prophet (saws) asked for a copy of the Torah and asked for the relevant passage to be read to him. And we know this about personal law from many other sources as well. In history, the various Islamic empires had systems wherein different faith communities could adjudicate according to their faith and traditions. Other examples including alcohol consumption and raising and consuming pigs. Non-Muslims are permitted to do this in Islamic states. They are permitted to have their own courts for civil law (marriage, inheritance, divorce, etc.) and for infractions considered a sin in their own religions, Muslim jurists would rule by that - but not when it was a sin in Islam (e.g. drinking alcohol or eating pork) (see here). This kind of tolerance is exemplary and noteworthy for all those who claim that Islam is oppressive or intolerant."

http://islam.stackexchange.com/questions/581/how-law-applies-to-non-muslims

In this case, Saudi Arabia determined that this type of action is punishable according to their civilian man made law. They shouldn't associate it with Islamic law, because it doesn't follow what the prophet practiced or what the religion dictated. That's why I call it a civilian man made law.

Although, the laws of the country should be respected, I personally believe this punishment doesn't fit the crime at all in this case. Even if it did, the man is in his 70s. Fine him and pardon him or in a worse case scenario, suspend his visa and send him back to England. He lived there for 25 years and served the country well, I am assuming. Have some common sense and mercy.

Finally, please don't assume that Saudi is the authority on Islam. Their government is not an Islamic government. There's not a true Islamic government in the world today as far as I know.

This is my opinion based on my research. I hope this helps and God knows best. Please correct me if I am wrong."