The gambling regulator will ask a court to force through its award of the next national lottery contract to the Czech-owned newcomer Allwyn, in a move critics say risks depriving good causes of up to £800m.

The Gambling Commission awarded the fourth national lottery licence to Allwyn earlier this year, triggering an immediate legal challenge from the incumbent Camelot and the media tycoon Richard Desmond, who also lost out in the competition for the lucrative licence.

The losing bidders are taking their case to the high court in October, with the Gambling Commission barred from moving forward with preparations to transfer the licence to Allwyn in the meantime.