Brussels — The relief displayed by Western European officials after a landslide victory for Britain's Conservative Party was visibly tempered by the sober expectation of tougher dealings with a strengthened Thatcher government.
A Labour Party victory might have created a tougher situation because of its objectives of withdrawing from the European Community and dismantling the British nuclear force. But few in Western Europe expected such a result when the ballots were counted.
Instead, they foresaw a second term for a government committed to deploying the controversial cruise and Pershing II nuclear missiles in Western Europe beginning in December; preserving Britain's nuclear strike force; and maintaining a tough posture in East-West relations. These views are shared by most West European governments.
But some West European sources are bracing for the resumption of a bruising political squabble with the Thatcher government in the EC now that the elections are over.
''The prospects of dealing with Maggie's demands and a strengthened hand are nearly as daunting as a Labour victory,'' noted a European official in Brussels.
An internal report prepared by one European government foresaw a troublesome period of tension ahead between Britain and the rest of the EC. The study noted that Mrs. Thatcher had shelved some of her insistent demands concerning Britain's refunds from the joint EC budget earlier this year to avoid disruptions that could undermine the reelection chances of West German Chancellor Helmut Kohl.
She and other British officials are said to be extremely irritated by Mr. Kohl's failure to reciprocate significantly during the British election campaign. So some analysts expect Mrs. Thatcher to become as strident in her demands for more EC money and reforms as she was three years ago.
Some even predict serious strains in the EC if Mrs. Thatcher resumes her original requests for fundamental changes in the European agriculture policy and spending. This would bring about a confrontation with France and other countries benefiting from the agriculture programs.