SPA-FRANCORCHAMPS, Belgium (Reuters) - Lewis Hamilton will start Sunday's Belgian Formula One Grand Prix from near the back of the grid as the world championship leader takes a hefty grid penalty for exceeding his allowed allocation of engine components.

"As far as I'm aware, we will be taking the penalty this weekend," the Mercedes driver told reporters at the Spa-Francorchamps circuit on Thursday. "I have no engines left."

Just how many places he will drop on Sunday's grid, however, remains unclear with a team spokesman saying the Briton was expected to start at the back or very close to the back of the grid.

Hamilton holds a 19-point lead in the standings over team-mate Nico Rosberg with nine of a record 21 races still to run.

The Briton has won six of the last seven grands prix and heads into the weekend gunning to become only the third driver in history to score a landmark 50th career win.