The woman was treated by paramedics after being rescued, with the pair believed to be aged in their 20s.

A spokesperson for Greater Manchester Fire and Rescue Service said: “A throwing rope was used by a member of the public and a victim was rescued from the water before firefighters arrived.”

Fire engines, a helicopter and an underwater drone were used to search the area, and a large cordon is now in place to prevent the public from accessing the reservoir.

Firefighters were on site for more than four hours on Sunday, the spokesperson added.

Police remained on the reservoir overnight with other emergency services including the coastguard and mountain rescue teams.