I've got a Boardman Comp Hybrid that I use for commuting to and from work, through central London, maximum distance is around 8.5miles each way.

Now the bike itslef has a 50/36 chainset and a 11/32 cassette, and last week I noticed I was only using 2 or 3 gears on the cassette – namely 13, 15 & 17 – while always being in the big ring up front.

I've had a look on Sheldons website about gear inches etc.

Today I decided not to change gear and left it in the 3rd position 15.

What I'm trying to figure out is, as it's pretty damm flat in the big smoke, would it be worth single speeding the Boardman.

Or shall I see if there's a swap on somewhere for a proper single speed roadie bike?

There's any number of cheap singlespeed 700c bikes around that you could go for, even a neat belt drive from Trek, which would be ideal as a fast, light low-maintenance commuter. Charge do the Plug, there's others I can't think of at the mo'. SS'ing the Boardman is obviously the simplest, cheapest option, but you'll need an EBB bottom bracket adaptor, or a tensioner, and I'd go for the EBB option, just because tensioners can be a pain sometimes with chain skipping. You can never have too many bikes… 😀

I can have too many bikes, especially when I've run out of room.

I think I might try the single speed option with a converter kit.

Saying that I do happen to have an 80's Raleigh bike built up as a single speed, but it's on 26" wheels, 1.75" slicks and summit like 38/18 for a combo, I'd spin out in about 3 seconds on that

Just make sure you get a sprung tensioner what ever one you go for
else you end up fiddling with them all the time as you chain stretches
a lot of the cheap kits dmr gusset etc are fixed

Surly's is the best imho
but probably the most expensive too
just go for whatever cheap sprocket and rear spacers you can get
not worth spending any extra there really