Ofcom announced on Thursday that as of April 2011 mobile customers will be able to transfer their existing phone number to a new network in just one working day.
In 2009, Ofcom proposed a revamp of mobile number porting practices of major mobile operators.
Current regulations give operators two working days to switch customers but Ofcom's regulation changes mean that from 11 April 2011, this will be halved to one working day.
"In 1999 it used to take consumers up to 25 days to switch their number to a new provider via a fax-based system. Nowadays, web-based systems mean that faster switching times can be achieved," said Ofcom in its statement.
To support the new legislation, networks have two hours to provide Port Authorisation Codes (PACs) by SMS or immediately over the phone.
Ofcom first proposed in 2007 to reduce porting times from two days to two hours, which was successfully challenged by Vodafone —backed by O2, T-Mobile and Orange— and withdrawn as a result.
Despite yesterday's announcement network operator 3 has spoken out against the move. "Ofcom's decision today has failed UK consumers," a spokesperson said in a statement.
The crux of 3's complaint is that customers in other countries do not need to ask network permission to keep their current mobile number.
"The donor-led porting system that Ofcom proposes to keep makes it difficult for customers to choose a deal that suits their needs. As mergers and consolidation reduce consumer choice, moving to a quicker consumer-friendly system becomes even more important," the company added in a statement.
Vodafone was more positive. "We welcome Ofcom's decision to enhance the current system for porting mobile numbers", a spokesperson told ZDNet UK.