The face on the screen was certainly familiar. So was the rich, deep voice. Only the setting was unexpected. But there he was, Walter Cronkite trailing after British Prime Minister Margaret Thatcher (and her husband Denis) through a muddy field of Cornish farmland, she in search of reelection and Cronkite in quest of a story.

Cronkite came to Britain at the invitation of "World-in-Action," one of the country's leading public affairs programs, to compile a personal two-part report on the national elections here. "The most trusted man in America," as the British media repeatedly called him, dutifully showed up at press conferences, rode campaign buses, canvassed with local politicians and generally joined the pack of news hounds on the hustings.

"Once more into the breach," Cronkite chuckled to his wife, Betsy, as they arrived in London on the supersonic Concorde.

And from all accounts, the experience was a rousing success. Cronkite drew uniformly favorable reviews from normally acerbic British television critics. "The smile, the moustache, the silver hair, the effortless old-world charm and courtesy, put him at a stroke points ahead of the mere politicians he was interviewing," wrote Richard Last in the Daily Telegraph.

For Cronkite, his relative obscurity in Britain was a decided plus. "It's the kind of thing he could never do in America," said Stephan Segaller, producer of the programs. Instead of anchoring from a studio and reading material prepared by a huge support staff, Cronkite, on the road, scrawled his scripts into a notebook and memorized them like any beginning TV street reporter.

Adopting the genial stance of a bemused outsider, Cronkite was able to provide viewers with insights into leading British politicians. Rising at a news conference, Cronkite asked David Owen, deputy leader of the Social Democrats, whether the party would support Labor or the Conservatives if it were to hold the balance of power in the next parliament.

"You are making an assumption," Owen replied tartly, reflecting tensions his critics say are seething below a cool surface, "and that is not an assumption you are entitled to make."

On a bus with Thatcher, Cronkite asked when the long-promised British economic recovery would start to help the millions who are out of work. "That's a nice answer," Cronkite said after Thatcher had finished a blandly noncommittal response that would have gone unchallenged by a British interviewer, "but I don't think it would do much for an unemployed person in England's Northeast."

On the whole, though, Cronkite came away impressed by Thatcher's leadership style. "People may not like what she stands for but, by gosh, they say, it's nice to have someone in there who sticks to her guns. I don't doubt that is a very attractive feature of her.

"I also don't doubt that she is a schoolmistress with her cabinet. Watching her in action at press conferences, you can almost see the ruler in her hand ready to smack a knuckle if someone gets out of line."

After a generation of covering U.S. national elections, Cronkite's exposure to the British system actually sharpened his understanding of some American virtues.

For instance, he noted that a person who wants to support the national policies of one of the parties here can only do so by voting for the local parliamentary candidate, "even if he's clearly incompetent." In a U.S. election, of course, voters are deciding separately who to put in the White House and who should go to Congress.

"Then, I always thought it would be better if we had more of a choice in our election campaigns," he said. " . . . But the more I see of the polarized Labor and Conservatives here . . . I appreciate the value of having our parties that basically meet in the middle.

"We cast a vote with the feeling that it's not really going to be disastrous if the other party wins, that we'll survive. Here, there's the feeling that if the other guys win, the country's very survival could be at risk. That's the danger of parties at the extremes of the spectrum."

As for his overall impression of Britain, Cronkite was struck by how widespread the feeling is that the country is in steady decline.

"Somehow they've got to be taken by the lapels and told, 'Look, you're all right, Jack. C'mon, you're doing better than a lot of other people are doing.'

"I suppose the problem was inevitable with the end of the empire--this is something that a lot of us were wondering after the war. I wrote about it as a young newspaperman--'What would the British be like when they realize they weren't king of the walk,' we asked. And now I suppose we know.

"They are depressed, psychologically depressed. It's unfortunate because there is great strength in these people and great charm. Sure they've been wrong as much as they've been right. But that doesn't deny them the future."