Del. Bob Marshall, a Prince William Republican and one of the most conservative voices in the House of Delegates, said Thursday that he would run for U.S. Senate this year.

Marshall has started to collect signatures to get on the June ballot, and said he will open an account to start raising money soon. But he will wait to issue a formal announcement. “I need to finish a few mechanical steps,’’ he said.

Marshall will take on former governor and senator George Allen, the heavy favorite to win the GOP primary. He said he would call Allen to tell him the news, and declined to criticize him.

Others in the race include: Jamie Radtke, former chairwoman of the Virginia Federation of Tea Party Patriots; Hampton Roads lawyer David McCormick; and Bishop Earl Jackson.

Marshall almost defeated former governor James S. Gilmore III to capture the Republican nomination for U.S. Senate at a 2008 convention to run against former governor Mark Warner (D). The margin was less than one percentage point.