When John Caulfield was working at the U.S. Embassy in London, he received a phone call from a distraught American couple who had been in England only a few hours.

"They were so excited about their trip, they went from the airport to a hotel, left their bags and grabbed the first taxi they could to take them to the Tower of London," Caulfield recalled. A few hours later, they realized they couldn't remember the name of their hotel.

While much of the State Department operates in the well-publicized world of international diplomacy, its Bureau of Consular Affairs handles the day-to-day chores that rarely attract attention but often touch the lives of millions of Americans.

This year, for instance, the bureau expects to issue more than 4 million passports, a record number, and to issue an estimated 7 million temporary visas and 425,000 permanent ones to visitors to the United States.

But the bureau's toughest jobs usually involve American travelers and residents overseas, according to Caulfield, a bureau spokesman who has served as a consular officer in England, Colombia and Portugal.

The 700 Americans and 1,950 foreign nationals who work as consular officers in the 250 U.S. embassies and consulates abroad are routinely called to help Americans who have been arrested, injured in auto accidents or robbed, or who need money to return home.

They work to keep track of the 1.8 million Americans who live overseas, and helped work out arrangements for the 10,000 U.S. citizens who died abroad last year.

The bureau is directed by assistant secretary Diego C. Asencio, who knows firsthand what it is like to be an American in trouble overseas. While serving as ambassador to Colombia in 1980, Asencio was held hostage by terrorists for 61 days.

Americans under arrest are one of the bureau's biggest headaches. Last year, 3,000 U.S. citizens were arrested while traveling abroad. According to Caulfield, the major categories of arrests included 35 percent for smuggling drugs, 11 percent for immigration violations, 7 percent for being drunk and disorderly, 6 percent for theft and 5 percent for credit card fraud.

Mexico arrests the most Americans, followed by Canada, West Germany, the United Kingdom and Thailand. Most foreign governments--Cuba is a notable exception--automatically notify the embassy if an American is arrested.

For decades, few Americans were arrested overseas and many did not think they had much to fear, Caulfield said. But when the number of U.S. citizens arrested on drug charges began to increase dramatically during the 1970s, the bureau launched a campaign to warn Americans about what could happen if they were arrested overseas.

Few countries provide a jury trial or accept bail, the bureau warned. Pretrial detention, often in solitary confinement, may last months, and foreign prisons often lack such facilities as beds, toilets and wash basins. Officials may not speak English, and travelers arrested on drug charges may face "physical abuse, confiscation of personal property, degrading or inhumane treatment and extortion," the bureau warned.

"Many Americans expect more from the U.S. government when they are overseas than when they are in the states," Caulfield said. For instance, he said, some expect the government to bail them out or provide an attorney. It will not, although it will give them a list of local lawyers. A consular officer tries to meet with Americans who are jailed, Caulfield said, to explain the country's legal system and to get them medical attention if they need it.

Because many foreign jails do not provide prisoners with enough food, the bureau operates a small Emergency Diet Assistance Program. The program supplies jailed Americans with vitamins and nutrients--for free, if the bureau decides that a prison diet is dangerously meager. American prisoners in Cuba, Thailand and Peru were the main beneficiaries of the program last year.

Since 1942, the bureau also has operated a little-publicized Repatriation Loan Program, which provides one-way airline tickets home to destitute Americans. Because Congress recently criticized the bureau's poor record of debt collection, the bureau has begun charging travelers interest on the money it lends and restricts their passports until the debt is paid.

The bureau spent $575,000 last year to help 1,650 Americans return home. They included women abandoned by foreign husbands, mentally ill people, and travelers who could not find anyone to give them a loan.

"These are really hard-luck cases," Caulfield said.

Recently, the bureau came to the rescue of a group from Boston. The trip organizer has been accused in a civil suit of buying their airline tickets with a bad check. As a result, the U.S. Embassy in London suddenly found itself responsible for 106 children and 13 adult sponsors, none of whom had a way to get home.

The bureau spent $44,000 to help care for the tour group and an airline agreed to fly it to Boston.