London — Britain's Liberal Party, a once-powerful movement that is again showing an impressive ability to flex electoral muscles, is entering an internal debate that may decide whether it really does have the prospect of long-term revival.
The first blow in what promises to be a season of searing party controversy was administered by its leader, David Steel.
With the Liberals' annual assembly set for next month, Mr. Steel accused Liberal grandees and local workers alike of immaturity and a failure to work seriously to advance the party's fortunes.
At the June election, working in harness with the Social Democratic Party (SDP), the Liberals managed to notch up a large slice of the nationwide vote. But, Steel charged in a ''confidential'' letter to his members of Parliament, some members of the party came close to sabotaging Liberal fortunes at the polls.
Liberal local government politicians, he said, had disowned their party's election manifesto. The Young Liberals group had complained that the policies on which their party was fighting the general election were not radical enough.
Steel is currently on a three-month ''sabbatical'' forced on him by the strains of the June election campaign. He is refusing to speak to newspapers or make open public comments on the internal problems of the Liberal Party.
But his four-page letter to MPs came close to threatening that he would resign the leadership of his party if senior politicians and grass-roots activists did not accept his full authority.
Among those lambasted were two leading Liberal MPs who have refused under Steel's leadership to act as party spokesmen in the House of Commons.
The Young Liberals are trying to take away from Steel the right of veto over the party election manifesto. Another section of the party is calling for the election of a deputy leader.
Both moves will be heatedly debated at the coming Liberal assembly. Some party insiders say Steel will certainly resign if Liberals vote to remove his power of veto over the manifesto.
Seasoned political observers here say the essence of the Liberal debate concerns what kind of party the members want. Activists in the Young Liberals and local politicians in the farflung cities and shires do not always see the party in national terms. They are committed to what they regard as Liberal ideology.
At a recent assembly, Liberals, inspired by a fiery speech, voted for free public transport throughout Britain. Steel, a hardheaded and ambitious Scot, regards such moves as immature and unbecoming a party with pretensions to national power.
He wants the Liberals, working with the SDP, to shoulder the Labour Party aside as chief opposition to the government.