Why Britain did not attack the French fleet at Toulon

Why did Britain not attack the surviving French fleet at Toulon?

Toulon was a high-risk target inside the Mediterranean, while other operations competed for forces and a submarine may have watched the harbor entrance.

Toulon posed a much harder target than the French anchorage at Mers-el-Kebir. A British submarine may have watched the harbor entrance, but a direct strike would have required entering a defended Mediterranean war zone while other operations competed for forces. The ships at Mers-el-Kebir could move directly into the Atlantic, which made their position more urgent from the British perspective. The surveillance detail remains uncertain, while access, risk, and competing priorities explain the operational distinction.