You can trade CME globex british pound, very liquid.
It has 1 tick value of 6.25$, that's like trading 6 mini
lots.
During Europen session and US overlap it's 1-2 pip
spread ($1.5 average spread + $0.75 commision & fees,...)
It's nearly 24 hour also, and spread don't widen much
like spot FX during news releases