Related Clues:

• Slit in jacket
• Very English conservationists getting voice
• Preventing core emission
• Opening taking the edge off occasion
• Voice pipe
• Air-hole
• Five for fifty in fast opening
• Heating or cooling outlet
• Outlet in Coventry
• Release anger
• Volcano's opening
• Get something off your chest
• Scream one's head off
• Come up for air, as a whale
• Opening item on programme -- opening put off