Okay there are some scary expensive Phil Wood ones but I seem to remember some saying there were some cheaper ones. I thought they were Echo but can't seem to find them on their site and Google is not being my friend at the moment.

Where can I get a fixed hub, with disc mounts to fit my mountain bike for less than £100 please?

The only one I've seen is the White Industries ENO eccentric disk hub (takes a splined cog and lockring I think, rather than screw on cog), but I'm not sure whether you'd get one under £100. Charlie the bike monger on eBay often has their stuff.

Apart from that, I'm sure someone will be along shortly to say "fixed wheel with a disk brake? on a mountain bike? are you on crack?"…

Fixed wheel = something different for the winter
Mountain Bike = It is what I have
Disc Brake = coz the frame is disc only and I don't fancy riding with no rear brake off road.

Will check out White industries. I have their ENO flip Flop which was fixed one side and free the other but obviously wasn't disc.

Surly make one – you should be able to get it via Ison for about £80.

http://www.selectbikes.com/index.php?act=viewProd&productId=99

*puts on flame proof suit*

Will you be using "those" lights again for added danger?

It does sound like a novelty rather than a niche, but at least you can put a freewheel on when you see sense.

I'm not sure if the Surly disc hub has threads for a lockring?

DMR used to do a screw on adapter to change one side of a flip flop hub to a 6 bolt disc mount, may be the cheapest option if you can find one?

The only ones available to my knowledge are Phil Wood and Paul Components.

This is certainly what Will at HubJub told me the other week and my own research.

I tell a lie.
Stoners link was wrong but they do do them apparently.
http://www.selectbikes.com/index.php?act=viewProd&productId=102

I'm not sure if the Surly disc hub has threads for a lockring?

It does, promise. You can just about make it out on the right:

clicky, scroll down a bit
Here at Ison distribution

how long before the "ive **** my knees by doing a skid on a fixed wheel and trying ot keep the pedals spinning " 😀

The Surly one does not appear to be available yet though.

Nothing on their website (other than the link above) and Ison don't have stock.
I'd rather have the Surly one than the Echo I've never heard of before. I assume from the description it's for Trials bikes.

Echo is a trials one. I didn't realise Surley had one on production yet but have emails Charlie the Bike Monger to find out.

echo are good kit

its fixed because alot of mod 20" run front freewheels and disks …

Have an echo one and it is a good piece of kit. Think i paid aboot £30 for mine

front freewheels, as in the cranks spin backwards but the chain doesnt move??

Have you looked on gearbox bikes, they use a fixie hub to keep the chain moving through the gearbox.

Selection of trials fixed hubs HERE