British Prime Minister Tony Blair will make an announcement about his future Thursday, his office said. Downing Street did not give details, but Blair is expected to announce a date for his resignation after a decade as prime minister. Blair's official spokesman said the prime minister would make a statement to Cabinet colleagues about his future as Labor Party leader. Blair is then expected to travel to his Sedgefield constituency in northern England to make a public announcement. Speculation about Blair's resignation date has swirled for weeks, and intensified after he celebrated the landmark of 10 years in power on May 1.