Are the British now the worst part of the ISAF?
I am British and I personally think so. The British military is vastly over-rated, and frankly a bit soft and not very tough or good at their job.
The Americans don't rate the British very highly, in fact, from what I've read I get the impression that American soliders out in Afghanistan rate the Germans as being tougher and a better asset to the ISAF than the British, who they see as being somewhat incompetent.
They like the SAS though, that's another story, but as for the average British grunt, they're not particularly impressed.
Also, during the Iraq War, when the British were put in control of Basra, the British military just couldn't handle it. Under their control the situation deteriorated significantly, to the point where they lost control and US military officials were left seriously questioning the British military's capabilities.
On the whole the British military is average at best.