It’s one of modern life’s perennial pains in the you-know-where. Your iPhone rings, you look at the screen and see a number you don’t recognize and because you’re an open-minded sort of person, you answer and immediately wish you hadn’t. Whether it’s PPI reclaims or mysterious accidents you were apparently involved in but remember nothing about, spam calls are a nuisance.

You can fight back, however. While companies making these calls are pretty savvy when it comes to the number they appear to call from, by blocking one every time you get an unwelcome call, you will reduce the frustration. Here’s how to do it.

1. When you’ve had a call you don’t want, whether you answered it and discovered it was a nuisance call, or whether you rejected it because you recognized the number, the first step is to open the Phone app again.

2. Tap in Recents at the bottom of the screen and locate the number you want to block – if you’ve just received the call, it will be at the bottom of the list. Tap the ‘i’ next to the number.

3. On the next screen, scroll to the bottom and tap Block this Caller. In the pop-up window, tap Block Caller. The number will now be blocked from calling you. To your network, any future calls will look like a missed call, so if the network texts you to alert you about missed calls, you’ll still get those texts – unless, of course, you block the network’s phone number.

4. To see a list of numbers you’ve blocked, go to Settings, scroll down and tap Phone. Now tap Call Blocking & Identification. To unblock a number, swipe left over it and tap Unblock.

To check who owns a number that’s calling you, the first step is to Google it. If it’s a known nuisance number, you’ll quickly see results from “reverse lookup” sites like WhoCallsMe or its UK equivalent. Tap on one of those results and you’ll be taken to the site and should be able to figure out from the posts left by other people who the number belongs to.