Yes, British citizens must have a valid passport in order to enter Iraq. In addition, your passport must be good for at least six months after your date of entry. Note that you must also have a visa to enter the country, which will cost between £30 and £70 depending on the duration of your stay. Single-entry visas are good for up to three months from the date of issue. A multiple-entry visa gives you entrance for between six months and one year. Note that the UK government strongly urges travelers to avoid Iraq as it remains a dangerous place for Westerners.