MARGARET THATCHER, the former prime minister, is leading an open rebellion against the European policies of her successor, John Major, claiming most British voters back her views.Exactly a year after the ruling Conservative Party dropped her as their leader, the Iron Lady of British politics told the House of Commons last week that a public referendum should be held to decide whether Britain should join in a closer political and economic union with its European Community partners. When Mr. Major replied that he was opposed to a referendum, and wanted the issue to be decided by Parliament, Mrs. Thatcher accused him in a television interview of arrogance. She insisted that Major should "listen to the people," and that at next month's EC summit at Maastricht, Netherlands, he should reject a single European currency and resist Britain's inclusion in a federal Europe. Prominent supporters of Major said they were appalled by Thatcher's open defiance of government policies. Sir Norman Fowler, a former government minister who advises Major on electoral strategy and is chairman of the Conservative European affairs committee in Parliament, said: "Her call for a referendum will be seen as an attack on the prime minister. If she goes on like this, she is going to lose us the election." The dispute between Major and Thatcher has exposed profound divisions within the British electorate on attitudes toward closer involvement in Europe. It also ends a 12-month period during which the former prime minister made most of her speeches overseas. Now, having prepared the ground for a Thatcher Foundation to promote her views abroad, she is apparently ready to intervene in British politics. The former premier's brush with Major occurred during a two-day House of Commons debate which the prime minister had hoped would close up splits in the Conservative Party on policy toward the EC in the run-up to Maastricht. Instead Major found himself heading a party in considerable disarray as Thatcher and her supporters continued to claim that voters were against closer ties with Europe and wanted a referendum. An opinion poll in yesterday's London Sunday Times appeared to back the claim. A Mori organization survey showed that 56 percent of the electorate wanted a referendum and that 32 percent opposed the idea. It also indicated that 54 percent would vote against adopting a single European currency, with 33 percent in favor. Thatcher's speech in the Commons debate was delivered from the back benches. Minutes earlier Major had attempted to argue that at Maastricht he could be relied on to resist pressures from Britain's partners for a federal Europe with a single currency. Thatcher's was an electrifying performance that outshone Major's and hijacked the debate, according to commentators and other Parliament members. She told an astonished house that if she were at Maastricht she would use her handbag to hammer home her view. Her subsequent attack on Major for rejecting her referendum call drew rebukes from senior Conservatives alarmed by her readiness to confront her successor. Terry Dicks, a senior Conservative backbencher, said: "She is misleading the people. She has never been in favor of a referendum before. She is beginning to sound like Ted Heath in skirts." (Edward Heath, Thatcher's predecessor as prime minister and Conservative Party leader, often attacked her policies when she held office.) But the timing and style of her sudden intervention in the European debate, close associates said, were carefully calculated. "She is a passionate believer in British institutions and British sovereignty," says one adviser. "She sees these under threat, and she is doing everything she can to defend them. If that puts her at odds with the government, so be it." The opinion poll findings make it clear that Thatcher is tapping into deeply held beliefs and emotions. The weekend Mori poll was one of several in recent weeks showing a distinct bias in the electorate against Britain's closer incorporation in Europe. In the House of Commons the so-called Euroskeptics number perhaps only 40 out of 650 members. In the countryside, however, it is a different matter. After last week's debate, Major obtained a majority of 101 for his policies, but he is aware that a general election must be held before mid-1992. An electorate that remains suspicious of Europe could turn sour if he signs agreements at Maastricht that undermine British sovereignty. The Labour opposition has been trying to play on Conservative Party divisions. Neil Kinnock, the opposition leader, argued in last week's debate that Major was more interested in papering over cracks in the Conservative Party than defending Britain's interests at Maastricht. John Smith, Labour's economic affairs spokesman, said last weekend that Thatcher's rebellion revealed a governing party in chaos. "The prime minister is caught in the hapless position of having so many backseat drivers he does not know where he is going," Mr. Smith said. As the row intensified, there were growing fears in financial circles that it could trigger a currency crisis. Last Friday the pound fell to 2.84 German marks, its lowest level since Britain joined the European exchange rate mechanism 13 months ago. If downward pressure continued, City of London dealers said, Major might be forced to increase interest rates - a move that would threaten the government's attempts to pull Britain out of recession. "The last thing Major wants is a sterling crisis just as he prepares to head for Maastricht," a dealer said. "It would gravely weaken his bargaining position."