If you want a decent futures broker, two I think are worth looking at are Velocity and IB. Velocity are I think particularly good for someone starting out or trading fairly small, as it's simple with pretty good rates (standard is I think $4.52 per RT, but that includes platform and data costs). IB is pretty good all round I think, but might not be the best option for a beginner.
If you want spread betting, there are as far as I'm aware two worth considering. Both are (or at least claim to be, and the claim is unequivocal) DMA outfits that simply route your trades through them, without interference. So you should be getting genuine genuine DMA, your orders actually enter the market and show up on the book etc, they cannot profit from your loss and so on. One is ibetfinancials, which is part of Kyte Group. This looks good, although requirements are quite high - account minimum is large, you've got CQG which is a great platform but costs about £400 a month and so on. However, the worst thing is that they don't segregate client money.
The other is KP Markets, who are new in the UK and probably a better choice for beginners or smaller accounts. The platform is a bit crappy but it's included in the price, and they do segregate.
The downside to DMA SB is cost versus a standard futures broker. Your RTs are going to be a few bucks more, which might or might not be a problem, depending. If you're scalping and taking 100 trades a week, it could outweigh any tax advantages, for example.
Those are 4 I'd say were worth looking at anyway, but as you know it depends on your circumstances and requirements.
By the way, I didn't mention Prospreads, because they're not (and in fairness do not claim to be) DMA.
