In a mystery shopping exercise, Ofcom found speed estimates were only provided by TalkTalk call handlers in 47% of cases and by BT Total Broadband sales people on 48% of calls.
Providers who were most likely to give customers an estimated broadband speed without prompting were Sky (72%), Karoo (76%) and Plusnet (67%).
The Voluntary Code of Practice on Broadband Speeds was formed in 2008 to ensure customers are informed of their likely maximum speeds before signing up to a home internet service.
A strengthened Code came into force in 2011, where internet service providers (ISPs) committed to give maximum speed estimates in the form of a range as early as possible in the sales process. A further review of the code will be carried out this year, as well as additional mystery shopping research.
BT and TalkTalk have agreed to amend their staff training and sales processes in order to remain compliant with the code, following Ofcom’s mystery shopping investigation.
As a result of the research, Ofcom says it will update consumer guides on choosing a broadband provider and broadband speeds to help people ask the right questions before signing up to a new service or switching provider.
The watchdog has also committed to having ongoing discussions with ISPs about the information their telephone sales people provide to consumers and how this could be improved.
Claudio Pollack, Ofcom’s consumer group director, says: “Our mystery shopping shows that, while consumer information about broadband speeds has improved in important areas, there is still more to be done.
“We are working with internet providers to improve information that consumers receive when they sign up to a new service and will continue to monitor this area closely.”
Ofcom also regularly publishes research into the actual speeds delivered by individual ISPs.
Last year, the body called for a crackdown on broadband advertising and it continues to push for ISPs to advertise their “typical download speeds” rather than the maximum to stop consumers being misled into thinking they have bought super-fast connections.