To setup your Windows Phone to receive email, please do the following:
From the Start screen flick left to reveal the App list.
Tap on the Settings icon .
Select the Email + accounts option.
Then select Other account.
Press the Email address box and type in your email address.
Tap on the Password box and then enter your password.
If the settings are not found, tap Try Again then select Advanced.
Then select Internet email account.
Enter a name for the email account in the Account name
Type the name that you want to appear when sending emails from this account in the Your name field.
In the Incoming email server field enter the incoming server details.
Select the Account type that corresponds to the incoming server you selected in Step 11.
In the Username field type the email address that you are setting up i.e email@example.com and in the Password field type the password for your mailbox.
In the Outgoing (SMTP) email server section enter: smtp.123-reg.co.uk
Select the options Outgoing server requires authentication and Use the same username and password for sending emails.
When you are finished tap Sign in to continue.
Your mailbox is now setup and ready to use on your Windows Phone.