EE shed 29,000 home broadband customers during the final quarter of 2012, it has been revealed.
The broadband provider - which offers fixed broadband in addition to its 4G mobile services - saw its home user base dip to 693,000 between October and December.
ISPreview.co.uk suggested the loss of customers may be directly related to the withdrawal of free home broadband for Orange mobile subscribers.
Orange - whose UK arm is owned by EE - scrapped this offer in October 2012, leading many customers to switch broadband provider.
EE's home broadband customer base has fallen from 1.14 million since 2007, but had recently returned to growth.
The firm attracted a net 1,000 new home broadband customers in the second quarter of 2012, and another 9,000 in the third quarter.
As such, the return to negative growth - albeit expected - is likely to be seen as a disappointment for the firm.
In terms of the wider business, EE Chief Executive Olaf Swantee said the company is performing well and has enjoyed a successful 12 months.
“In the past year, we delivered solid financial performance, underpinned by good progress integrating the business and success in attracting high value customers," he stated.
"At the same time, we built a strong platform for growth, launching a new company, new network, new customer brand, new retail estate and being the first to provide UK consumers and businesses with 4G mobile services alongside fibre broadband."