Britons, who publishing pundits say have a resistance to weekly news magazines, woke up Friday morning to find 400,000 first copies of hard-driving, Anglo-French businessman Sir James Goldsmith's Now! on their newsstands.

At a time when the woes of British journalism are only too apparent, with the Times of London and commercial television closed by strikes, Goldsmith, a veteran of libel actions against the press, launched a glossy, 142-page British-slanted mixture of news, Conservative political views, criticism and gossip. The venture is backed by $3 million in advance advertising -- and by Goldsmith's three year's experience as publisher of L'Express, the French news magazine.

Some are saying that Goldsmith has backed a loser, but they are not saying it too loudly yet. The 46-year-old Goldsmith is a man who has proved nay-sayers wrong before.

He built up a number of downtrodden food companies in the 1960s into the Euro-giant, Cavenham Foods, with sales of more than $3 billion in 1975-1976, having started his business life as a 16-year-old Eton dropout with $18,000 in racetrack winnings.

What he has done well all his life is gamble and that is what he is doing with Now!

Although Goldsmith is a European-based businessman, he owns the Grand Union food chain in the United States and is known to be interested in other ventures there. He unsuccessfully bid for the Village Voice and other papers picked off in the end by Australian Rupert Murdoch.

The first edition of Now! leads with an in-depth investigation of Iraq's intelligence penetration in Britain and Europe, heavily laced with supposed KGB connections. There is, however, no mention of the election of the new reorganization of British Leyland, nor of a major strike by Britain's engineering workers -- clear lapses for what is supposed to be the British news magazine.

Press reaction to the magazine has been a mix of goodwill and reservations about its style and format.

In Friday's Daily Mall, Harold Evans, editor of the strike-silenced Sunday Times, welcomed Now! but added, "It does not yet tell us [as it claims] 'what will happen and why and how.'"

Goldsmith's response to his critics is that the format of Now! is based on the successful L'Express. He hopes for an eventual British readership for Now! of 250,000, but says he will support the new venture as long as it "feels like it has life." Yet Goldsmith is the first to admit that he is taking a risk.

Advertisers say he will be lucky to get a circulation of 100,000 in a country where the Sunday paper traditionally provide national news coverage. At the same time, they welcome a new journal in which to sell their products.

Questions of format, risk and business sense aside, his entry into British journalism raises other issues. In 1976 Goldsmith sued the British satirical magazine Private Eye for libel. Private Eye had accused him of having conspired to hide an aristocratic friend of his, Lord Lucan, who was being sought for murder.

That suit was technically resolved in 1977 with Private Eye paying Goldsmith about $60,000 for legal costs and taking out a full page ad apologizing to him.

The feud, however, has gone on, with Goldsmith charging that Fleet Street (the home of most British papers) is "infected with a cancer" of "anonymous" backs who secretly work for Private Eye while also writing for other papers. Goldsmith has asked Fleet Street editors to fire journalists whom he suspects of helping Eye.

Richard Ingrams, editor of Private Eye, says of Goldsmith's attacks, "He has a bee in his bonnet about us. We mad one crucial mistake but we did not treat him unfairly." Ingrams also says that he tinks Goldsmith is "using -- Now! simply as a political platform to launch himself into public life."

Goldsmith's feud with Private Eye, coupled with an incident last year in Paris when, as he himself says, he "manhandled" a British photographer, has left doubts in the minds of journalists here about his attitude toward the press.

Goldsmith answers his critics by saying that his French magazine L'Express offers a range of political views and is respected in France. He also says that he has hired 71 professional journalists -- at salaries of up to $55,000 -- and they would not have joined him had they felt they were just his puppets. American columnist Art Buchwald, at least, seems to have found the conditions attractive enough to sign on.

Goldsmith admits that he started Now! in part to "influence" British public opinion. He is candid about his political aims and says he would not mind entering politics -- his father was a Conservative member of Parliament -- and says he wants his magazine to "feel strongly about things."

To some extent Goldsmith, who is part French, appears to be caught between old-fashioned British distaste for aggressive outsiders and his own desire to be part of British public life.

With a reputation for tough, profitable business dealings and a proven record of suing journalists who he feels have wronged him, Goldsmith is a hero to some British businessmen. At a celebratory champagne breakfast to kick off Now! Friday, he smiled as Bert DeVoss, managing director of a london advertising agency, thanked him for his "stupendous ability to stand up to pinko journalists."

Whether Goldsmith's new magazine will be "standing up to pinkos," launching him into politics, reporting the news, or going bust, remains to be seen. He is something of a Henry Luce figure and regardless of what happens to Now! there is no doubt that he will be around for a long time.