Sen. Charles Colgan (D-Prince William) said Friday he plans to sign off on the compromise on state budget reached late Thursday even if it means going against his own party.

Sen. Charles J. Colgan (D-Prince William) (Bob Brown/Associated Press)

A majority of House and Senate budget conferees agreed to a two-year, $85 billion spending plan, even though it did not include a Democratic priority — $300 million for Metrorail to Dulles International Airport.

Colgan said he plans to sign the conference committee report, which will allow the General Assembly to return next week to vote on the bill. He was slightly less sure about whether he would vote for the budget, but repeatedly said he was pleased with the compromise.

“I put a lot of work into the budget, hours and hours, late nights,’’ he said.

Republicans need at least one Democrat to vote for the budget for it to pass the Senate, which has 20 Republicans and 20 Democrats.

All 20 Democrats have voted against previous versions of the budget two times. Colgan said he was not worried about members of his party’s reactions to his possible “yes’’ vote.

“They’ve been mad at me before,’’ he said.

The deal came in the midst of a special session called after Senate Democrats blocked passage during the regular session in a dispute over spending and committee assignments

Colgan’s likely support means Republicans have the 21 votes needed for passage in the Senate. Passage is not in doubt in the House, where Republicans enjoy a 2-to-1 majority.

Colgan said he was not promised anything for his vote, though Republicans have offered to let him co-chair the Finance Committee along with Sen. Walter Stosch (R-Henrico). “I’m pretty happy where I am,’’ he said.