Re: GCHQ?
Since the initial landing point on this side of the pond is in the Republic of Ireland (Killala, County Mayo), GCHQ are unlikely to get first dibs at the traffic on that system - although there is fairly chunky backhaul to the UK.
You might want to look at what Stiúrthóireacht na Faisnéise (and possible the Garda NSU) are doing with regard to Cable Landing Stations in the ROI, and the status of Irish laws regarding surveillance and storage of traffic.
Biting the hand that feeds IT
