For some time now WhatsApp has allowed users to pull back and delete sent WhatsApp messages even after they have been delivered to the recipient's phone.

It's been a relief for the hot-headed, who immediately regret their fiery text, or for those who have sent messages to the wrong person, or simply said something they shouldn't.

Unfortunately, WhatsApp isn't able to actually turn back time, so the process is useful only when the recipient has not already read your message. But the app has a useful system that lets you know whether or not a message has been read, with a single grey tick showing it has been sent, two grey ticks that it has been delivered, and two blue ticks that it has been read.

There is a caveat, and you must act fast: delivered WhatsApp messages can be deleted only up to seven minutes after they have been sent.

To delete a WhatsApp message tap and hold to select it, then press the bin icon. Choose 'Delete for everyone'.

In the next few months WhatsApp is expected to beef up this neat feature by allowing you to predetermine how long messages should be visible before they automatically self-destruct. You will be able to select options between 1 hour and 1 year in its currently in-beta Disappearing Messages feature.

What you need to know about deleting WhatsApp messages

The new feature can be a lifesaver, able to rescue you from the horror of having written something you immediately regret, or perhaps a message you sent to the wrong person. But it can also create some problems, because whenever you delete a message that has not been read WhatsApp will place a marker in the conversation notifying your recipient that a message has been deleted. If you do not see this message then you know you were too late: the message had already been read.

It's usually pretty easy to tell when WhatsApp messages have been read - by default you'll see a single grey tick next to a message when it has been sent, two grey ticks when it has been delivered, and two blue ticks when it has been read. But supposing they read the message in the exact moment that you delete it, or either party has disabled read receipts, you may not get this warning.

The other thing to note is that WhatsApp has recently changed the length of time for which it will keep attempting to delete sent messages, and it will now give up after 13 hours, 8 minutes and 6 seconds. Although the deletion process should work instantly if both parties have their phones switched on and are connected to the internet, should someone receive your message and immediately switch off their phone (or their battery runs out), or go out of range, that message might not actually get deleted.

How to delete a sent WhatsApp message after seven minutes has passed

In order to delete a sent WhatsApp message you must give the instruction within seven minutes of sending it. So when the butterflies set in at 7 minutes and 3 seconds, are you screwed?

Apparently not, according to @AndroidJefe. He's found a trick to extend this time period, but as always it works only if the message has not already been read.

Turn off Wi-Fi and mobile data

Go to Settings, Time and Date settings and roll back the date to a time before the message was sent

Open WhatsApp, find and select the message, tap the bin icon and choose 'Delete for Everyone'

Turn on Wi-Fi and mobile data and reset the time and date to normal in order for the message to be deleted on WhatsApp's servers

Read next: How to delete a sent Facebook message