Police said mobile phones, 2,000 Australian dollars (£1,060) in cash, and documents described by officers as drug ledgers were also seized at the hotel.

Detectives had earlier found 2kg of ketamine at a short-term stay unit in Artarmon on Sydney’s Lower North Shore, along with scales, gloves and other paraphernalia.

Police have claimed the couple travelled to Australia “for the sole purpose of taking part in the distribution and supply of large commercial quantities of prohibited drugs”.

A Foreign Office spokesperson previously said: “We are supporting two British nationals detained in Australia and are in contact with the local authorities.”