Is this a hoverfly larva?

I found this, what I think is a hoverfly larva, on a nasturtium leaf today. My nasturtiums are flowering well for the time of year, but I am getting a few blackfly on them, and keep rubbing them off. I wasn't sure what this was, but after photographing it I think it is a hoverfly larva, which was keeping the blackfly numbers down. After photographing it I put it back on the nasturtiums.

 

I always thought hoverfly larvae were those rat tail maggots you find in rotting vegetation especially nettle brew.

 

There are a lot of different hoverfly species and there larvae are quite varied, some scavengers, some predatory and some vegetarians.
The rat tailed maggot is the larvae of the Drone Fly a hoverfly that looks like a male bee as an adult; there are a number of other hoverflies with similar looking water living larvae.

 

I was watching a programme some time ago and I think it was in Scotland where a specific hoverfly larvae can only live in the hollow rotting stumps of felled trees.