What is the significance of the five-minute bell at Lord’s ?

What is the significance of the five-minute bell at Lord's ? #Cricket #India #England #INDvENG #INDvsENG #ENGvIND #ENGvsIND #Lords #RahulDravid
Rahul Dravid ringing Lord’s bell

Lord’s five-minute bell is rung before the start of a day’s play during Tests by an international cricketer, administrator or “well-known enthusiast of cricket” to signify the imminent start of play.