The stepson of a Brit billionaire on board the missing Titanic submersive vessel has said he 'hasn't slept in days' after hitting back at online trolls.
Billionaire businessman Hamish Harding is among the five people who embarked on the OceanGate vessel on its undersea mission down to the historic shipwreck, before contact was lost on Sunday afternoon.
Rescue crews have embarked on a frantic attempt to find the craft in the hours and days since, with emergency oxygen supplies expected to run out at around midday today.
