Mers-el-Kebir as a necessary but corrosive mission

Why did Britain not pursue or seize more of the French fleet after Mers-el-Kebir?

The immediate goal was containment, but the operation was morally difficult and badly affected Somerville.

Mers-el-Kébir and the containment of the French fleet were distasteful but strategically necessary. Once damaged ships were moving to Toulon, Britain preferred them bottled up there rather than dispersed where the Axis might gain access. Somerville disliked the task and appears to have become less effective afterward. Another commander, perhaps Cunningham, might have carried out the coercive mission with less lasting personal damage.