The likelihood that Margaret Thatcher will have a fellow woman prime minister to deal with in Western Europe during her term is high, and the smart money is on French Health Minister Simone Veil.

She has had an unbroken five-year run in the opinion polls as the most popular French politician.

Veil could not be more different in background and personality from Britain's "iron butterfly." She has iron of her own, acquired as a young Jewish inmate of Auschwitz concentration camp, but unlike Thatcher, Veil is a pragmatist and not an ideologue.

Veil also has an unquestionably fundamental attachment to social concerns that is rare in France for someone who does not claim to be on the left. But she preaches the need for individual initiative and self-help that sounds just enough like the Thatcher message to raise eyebrows in a France addicted to government decision-making.

Veil is heading the campaign of President Valery Giscard d'Estating's own party in the first direct elections for the European Parliament, which amounts to the legislature of the European Common Market.

That body has largely been a powerless echo chamber. Its status is bound to be enhanced by universal suffrage, a prospect that has been turned into a major issue in France by Gaullist and Communist opposition to anything that suggests surrendering any sovereignty to an international body.

Veil's willingness to throw her non-partisan image into the electoral balance is a major plus for the Giscard ticket, and also a test of whether her personal popularity can be translated into electrol magic.

Veil's popularity came almost overnight when in 1974 as the new health minister, she defended the Gisard government's most liberal measure to date - the first law authorizing abortion in a Roman Catholic country. There was a television strike and the only thing to watch was the new woman minister in the National Assembly, or parliament.

Perhaps only she could have persuaded the largely male assembly to pass the law legalizing abortion in the first 12 weeks of pregnancy.

As she spoke, a male opponent of the bill yelled, "You are sending babies to the crematories." The survivor of Auschwitz just stood silent at the lectern, with tears in her eyes.

She knew how to exploit her popularity to get other unpopular measures passed, such as on family planning and contraception, and another reducing the outlays of a social security system going bankrupt with rising medical costs.

She refused in an interview to single out any particular accomplishment in five years as health minister, stressing instead "a consistent line in all domains to try to make people become conscious of their personal responsibility" - this in the ministry that is the heart of the French welfare state. But, she stressed, she opposes old-fashioned laissez-faire capitalism that neglects the need for social justice and human solidarity.

"I try," she said, "to place myself between" recognition of the state's "great obligations" and the individual's responsibilities to himself and society-standard fare in American political rhetoric but rare in a France nurtured on state aid.

She often has used her influence inside government councils to act as a moral conscience, pleading for governmental human rights appeals for Soviet dissidents and Latin American victims of rightist repression.

She was instrumental in forcing French television to show the American-produced "Holocaust" series on the fate of jews in Nazi Europe after the head of all three TV stations had mad public statements refusing to show it.

Basic anticommunism is a constant in her statements in a country where it is frowned on by the intellectual establishment. She deplores what she call U.S. failure to play a greater leadership role.

A recent opinion poll showed that 58 percent of French citizens say they want her to play a greater role in French government-11 percentage points more than her nearest rival, Socialist Michel Rocard. Until now appointed to public office, she is for the first time putting her popularity to the test of an electoral campaign. She expects it will result in a sharp and sudden drop in her standing in the polls, she said.

She passed her first test when she appeared in a televised debate with three of France's most experienced political infighters: the chiefs of the three other main party lists in France, Gaullist Jacques Chirac, Socialist Francois Mitterrand and Communist Georges Marchais. It was the kickoff of the campaign for the European elections on June 10.

Veil did more than hold her own. A poll afterward showed that 33 percent of the viewers thought Veil had been the best of the four, 25 percent Chirac, 23 percent Marchais and 19 percent Mitterrand.

At 51, Veil is a handsome woman. She dresses elegantly in classic Chanel suits and long-sleeved dresses that always hide the concentration camp number-78,651-tattooed on her forearm.

She is a feminist. In the French style, that includes a reaffirmation of feminity and the usefulness of difference in the ways men and women approach problems.

Thatcher's victory, said Veil, is "one of a kind," comparable to the special circumstances in the elections of Golda Meir in Israel and Indira Gandhi in India.

"It's not at all a sign that in Great Britain or in Europe generally women play a role as important as men, or even a really important role at all."

It is hard for women to get ahead in French politics, Veil said, not only because they are tied down for a long period raising families, but also because "there are still very few husbands willing to let their wives out to attend political meetings at night."

It almost sounded like a description of her own family situation. Her husband of 35 years, Antonie, 52, heads the French airline UTA. But for years, he was the politician of the family, serving as an executive aide to a number of leading middle-of-the-road politicians. While she was raising three sons, now in their late twenties and early thirties, he was bringing home political cronies to negotiate deals.

He apparently had a hard time at first accepting the idea that the one brilliant political career in the family would be hers, not his.

He dissauded her from becoming a lawyer and urged her to study to be a judge instead because it involved less time away from the family. She in turn discouraged him from seeking elective office.

There are those who trace her distaste for conventional party politics to the period of Antoine's political hey-day. In any case, one source of her popularity seems to be the echo she finds in public opinion for her use of the word "politician" as if it were unclean.

"For me," she said, "politics is ideas. I would like to be able to be committed exclusively to defend ideas. For perfectly natural reasons that I accept-but which I have great difficulty in going along with personally-there is a tactical element so great that you often wind up wondering what ever became of the ideas."

Despite her accent on the need for individual responsibility, she is a product of the tradition of service to the state inculcated in high French civil servants. She has served as a prison administrator, a drafter of bills in the Justice Ministry and as a member of te governing board of state radio and television.

She is a hard taskmaster an admits to a quick temper, a perfectionism that involves her in details that should be left to subordinates and a tendency to keep her staff at a distance, almost never addressing them by their first names.

Even her reading for pleasure is serious-Marcel Proust and Henry James.

Although it is an open secret that Giscard has long toyed with making her prime minister, she still professes to resist the idea. But cracks are beginning to appear in her resistance. She probably has time because for now Premier Raymond Barre is useful as a political lightning rod for a series of unpopular economic measures deemed necessary to modernize the French economy. CAPTION: Picture, Health Minister Simone Veil, a major figure in French Government for years, is testing her electoral Power.UPI