Deputy Leader of the Labour Party Tom Watson has called for all online casinos to re-apply for their licenses in Great Britain.

Watson, an outspoken critic of the gambling sector in Great Britain, has confirmed on social media he wrote to Culture Secretary Jeremy Wright because "over one third [of operators] are failing their customers."

The Gambling Commission last week fined four online casino operators £4.5m ($5.8m) in total, with the biggest individual fine within that category amounting to £2.2m.

The Times, which gained access to Watson’s letter, has quoted its own research to show online casinos pay £120m to sponsor Premier League football clubs overall, while only contributing £50 per team to Britain’s biggest gambling charity.

Watson is quoted as writing in the letter: "A gambling license should be a hallmark of credibility and trust. It should not be seen as an opportunity for operators to push the limits of their conditions and responsibilities.

"The regulator cannot be in a position where it is continually playing catch-up to an opaque and agile global industry. We need a structured response to the situation. This will require a total overhaul of our register of current remote sector licenses.

 "This review would be an opportunity for existing remote license holders to re-apply for the privilege of operating and marketing in the UK."