WRITING TRADED OPTIONS for income

nice and informative posts today; just read them at local library after a days travel.
I also recall seeing appreciable discrepancies between IG and Cantor a while ago but it's too far in the past to recall exact figures.
I don't think you can describe it as a true arbitrage opportunity , since (as stated above) there are execution risks at the open and closing of the positions with two brokers and the inevitable timelags of dealing with one broker and then the other .
chartrader: i don't suppose it's that difficult for them to guess the direction of your trade . When you already hold an open position in VOD (say) it is more probable that your next trade will be to close the position. That is why ask for a quote of the spread before I give my account details