Buying a secondhand phone? Here's how to check whether it's been reported lost, stolen or is blocked before you buy. Plus: How to find a phone's IMEI. Also see: Best old phones - best phones to buy secondhand

What is an IMEI?

All phones feature a unique IMEI (International Mobile Equipment Identity), which is a string of 15 or 16 digits that identifies the device on a mobile network. It is transmitted to the mobile operator as soon as you switch on your phone.

How to tell if a phone is lost, stolen or blocked before you buy

If your IMEI has been reported lost or stolen, or the IMEI is blacklisted, you won't be able to register it on the mobile network. The same applies if your phone's IMEI is lost or missing, which can happen when flashing a custom ROM.

Network operators use this IMEI to verify whether a phone has been reported lost or stolen. For this reason you may choose to check whether any secondhand phone you are considering buying has a dodgy IMEI. You can do this via a service such as Checkmend, and all you need is the IMEI from the seller. Also see: How to find my phone: How to track a lost iPhone, Android or Windows phone.

CheckMend

Checkmend will tell you whether a phone is EE-, Vodafone-, Three-, O2- or Global GSM/LTE blocked, has had multiple registered owners, has been reported stolen to the UK Police, has previously been recycled or refurbished, has been filed as part of an insurance claim or has outstanding finance on it. It will also confirm the make and model, which may help you work out whether the phone is a clone or counterfeit. Checkmend charges £1.99 for a single device, but bulk discounts are available.

To check a phoneusing CheckMend simply navigate to the website and click on 'Create a single CheckMend history report now'. On the next page enter your email address, the phone's make and model and IMEI. Enter the Captcha, tick the box to say you accept the T&Cs, then click to pay by card or with PayPal.

CheckMend also lets you check a phone by text message, although this service is more expensive at £3 (plus your standard network charge). To check a phone send a test message containing the word check followed by the phone's IMEI followed by your email address to 83010. For example, check 123456789123456 [email protected].

How to find a phone's IMEI

There are several ways to find a phone's IMEI.

• Dial *#06# on the keypad

• Go to Settings, About device, Status, IMEI information, IMEI

• The IMEI should be printed either on the back of the phone or underneath the battery, if the rear is removable

• It will also be printed on the box it was sold in, provided you still have it

• If you still have the receipt for the phone the IMEI may also be printed here

If your Android phone is missing its IMEI and you no longer have the box it came in and cannot access the internals to read the printed code, a good place to check is Google Dashboard. If you've used that device to sign into your Google account then the IMEI should be listed here.

Go to Google Dashboard, sign in with your Google account, then click on the drop-down beside Android to see a list of devices that have been signed into using your account.

Google Dashboard

Read next: How to spot a tech fake

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