LONDON — If British plans for leaving the European Union have been a dance of the seven veils, the British government removed one of them on Sunday, letting slip to news media that Prime Minister Theresa May is likely to choose to exit Europe’s single market and its customs union — a so-called hard Brexit.

Mrs. May is scheduled to make a long-awaited speech on her plans on Tuesday, but the British weekend papers and Sunday news programs were briefed by Downing Street about the main lines of the policy, and some published selected quotations of what Mrs. May is scheduled to say.

Officially, a government spokesman on Sunday called the reports “speculation” and emphasized only the extracts of the speech that were leaked by Downing Street itself, with Mrs. May calling for British unity “to make a success of Brexit and build a truly global Britain.”

Those extracts were not explicit on the single market or the customs union, but the Sunday newspapers, which receive their own briefings from the government before publication, took much the same line: that Britain is headed for a sharp break with Europe after a transitional period.