In the past the UK's balance of payments has been buffeted by wars and, more recently, the price of oil. Now, though still slightly in the red, it is relatively stable.
One of the earliest definitions of the balance of payments appeared in 1668 in Sir Joseph Childe's A New Discourse on Trade. Three centuries later his description still holds as both accurate and admirably concise: 'Something whereby it is known whether this kingdom gaines or loses by foreign trade'.
International trade has existed for as long as the British have been seafarers. Roman rule aside, however, its impact was relatively slight until the end of the Middle Ages. It was not until the 17th century that foreign trade came to the public's notice. Pundits proliferated, among them the novelist and pamphleteer, Daniel Defoe, who lambasted restrictive French practices and concluded that 'no trade was better than a destructive one'.