Related Clues:

• Clamour created by ex-PM in speech
• Palindromic tugboat sound
• Horn’s high-pitched note
• Siren noise
• Sound from a small horn
• Use horn, coming and going
• Lay on, as a horn
• Friendly nudge at a green light
• Sound from a tugboat
• Horn sound on the river
• Train whistle's sound
• Sound from a train whistle
• Blast, as a boom box