Verwaayen told ministers of Parliament on Tuesday that it would be "a disaster" for the United Kingdom if BT's network operations were split off into a separate business, as some of its rivals say is needed to create competition in the U.K. telecoms market.
Communications regulator Ofcom has threatened to begin the process of breaking BT if the telco fails to give other operators fair access to its network. Verwaayen insisted on Tuesday that BT's own proposals to create a separate "access division" made more sense.
"[Breakup] would be painful, costly, very slow and cumbersome," Verwaayen said, appearing before the trade and industry select committee at Parliament.
Ofcom is weighing this issue as part of its strategic review of the telecommunications market. The regulator told the committee last week that it is still working out whether BT's proposed "access division" would work in practice.
Verwaayen also claimed that the move would hamper BT's attempts to upgrade to an IP-based infrastructure.
Graeme Wearden of ZDNet UK reported from London.