Raleigh Airlite 100 possibly single speed project

This will be an easy singlespeed project if the rear wheel takes a cassette (not a freewheel).

Check that first, it is the case, you just need a singlespeed kit for the freehub (about £15) and 5x single chainring bolts to remove one of the front chainrings.

Once this is done, you can look at risers and other bits.

Gearing wise, I find 65 to 75 Gear Inches to be good around town - use this calculator to see what the GI will be before buy your singlespeed kit:
http://sheldonbrown.com/gears/

Yeah, as far as I'm aware its a cassette, thanks for sharing that link I will look into it

Good buy for £50: they're quite rated as entry level road bikes.

I've got a single speed kit with different cogs, for a freehub going spare: give me a shout when you figure out your gearing.

I will keep that in mind, thanks.

It will also need a chain tensioner. Right?

I'm hoping to be able to pull it off without any chain tensioner.