Riyadh

Alcohol: do not bring any into the country and do not arrive under the influence. Alcohol is on the FCDO's list of goods it is illegal to import, it is illegal to drink alcohol or be drunk in public, and you can face severe penalties including prison for brewing, possessing or selling it.

Drugs: there is zero tolerance and the penalties are severe. You can get a prison sentence of up to five years and a 30,000 Saudi riyal fine for possessing even small amounts, and dealing or smuggling can result in a death sentence. The US State Department lists marijuana, cannabis and CBD products and their derivatives as illegal, with criminal sentences of many years in jail or death.

Prescription medicines: many need approval before you bring them into or out of the country, and the US State Department advises registering listed prescriptions on the Controlled Drug System website before you travel, a process it says may take several weeks. The FCDO says some prescribed and over-the-counter medicines are controlled substances, that UK prescriptions are not accepted, and that you should carry an official prescription, hospital note or GP letter stating the amount prescribed, the drug and dosage, your doctor's signature and a clinic or hospital stamp.

Social media and exit bans: Saudi authorities may detain you over online activity they consider critical, offensive or disruptive to public order, and the State Department says this may include posting, re-posting or liking, and comments posted while outside Saudi Arabia. It records prison sentences of up to 45 years for social media activity. Separately, exit bans over unpaid debts, disputes, legal cases or investigations can stop you leaving, they can last years, and the State Department notes many travellers do not find out about one until they go to the airport.