'05' - VoIP and Corporate Phone Numbers

UK telephone numbers starting with '05' are split into two seperate categories:

'055' - Corporate Phone Numbers

'055' numbers are intended for use by large organisations who need a dedicated block of numbers that are not geographically linked to a specific location. These could be used, for example, for an internal phone network covering various branches throughout the whole country.

Despite '055' numbers being available for a number of years, very few companies have made use of them, with most companies prefering to use '03' or '08' numbers instead or acquiring a single large block of normal geographic numbers in an area that has lots of spare capacity. There are currently 4 separate series of '055' numbers in use:

  • 05511 numbers
  • 05516 numbers
  • 05555 numbers
  • 05588 numbers

Currently, 50 blocks of 10,000 '055' numbers have been allocated to providers for use.

'056' - VoIP Numbers

'056' numbers are officially designated for use for 'location independent electronic communication services', but are mostly used for VoIP services. However, since late 2004 such services have also been able to use '01' and '02' geographic numbers.

There are currently 5 separate series of '056' numbers in use:

  • 05600 numbers
  • 05601 numbers
  • 05602 numbers
  • 05603 numbers
  • 05604 numbers

Currently, 339 blocks of 10,000 '056' numbers have been allocated to providers for use.

Until their withdrawal in 2017, '0500' numbers were used for freephone services.