Soult escaped, but his incursion into Portugal had cost him 6,000 of his 25,000 men, just under half of those being killed or captured during the retreat. He also lost his baggage, his transport and all fifty-four of his guns. It was, indeed, a broken army and a massive defeat, but it did not end French designs on Portugal. They would be back the following year and would have to be thrown out again.
So Sharpe and Harper will march again.