The laws in other countries are immaterial.

Let us postulate that, for the purpose of discussion, a certain person is a member of a culture where the legal age of consent is very clearly set at 16 years, and where the concepts of statutory rape, child abuse, paedophilia, abuse of trust, coercion, blackmail, intimidation etc etc are clearly defined and understood. Let us postulate a sexual act, or acts, perpetrated by this person upon a young person who is younger than the age of consent in this culture/jurisdiction, and that the person in question can be expected to have had a good idea of the young person's age.

That person's frame of reference should be the mores of the country in which he lives and in which his actions took place.

Express and Daily Mail readers bay loudly enough about foreigners "coming over here" and expecting not to have to live by our laws. Is anyone seriously suggesting that a British paedophile should be able to use foreign laws as an excuse? Personally, I would not leave my children in the care of anyone who would support such a defence...

People mature at different rates. There is no practical way that the laws put in place to protect the vulnerable can make allowances for that difference in maturity amongst individuals, thus we have a fairly arbitrary age of consent. Arbitrary it may be, but it is also a rational and sensible compromise - a 'best guess' or average. It is imperfect, but well meaning and a genuine attempt to afford some protection from abuse. It is the law we have and it is the law by which British citizens must abide.