The ‘Office Anywhere’ bolt-on can be attached to the BT Business One plan, aimed at businesses that spend £500 and above a year on internet, mobile and fixed-line.
It includes unlimited email and internet, a handset upgrade to the HTC S710 or HTC S620 smartphones, and unlimited calls between BT mobiles and back to the office landlines.
Inclusive minute bundles include calls to the USA, Canada and Ireland. The bolt-on also allows unlimited one-hour VoIP calls to UK landlines, but it is available without this feature as a £5 monthly bolt-on.
BT Group chief of mobility and convergence Steve Andrews said: “This is part of our strategy to promote products apart from voice for small businesses.
“We sell BlackBerry largely to corporate users, but there wasn’t something as easily available to help small businesses to function like corporates.
“We are also increasingly signing up customers with businesses of around 70 handsets.”