The Foreign Office has pledged to continue its campaign to convince EU member states to add Hizbollah to a list of terrorist organisations, despite opposition emerging this week.
Initial EU discussions on whether to proscribe the Iran-backed group in its entirety ended without agreement in Brussels on Tuesday.
Reports suggested Italy was among six countries to raise concerns over possible increasing instability in Lebanon if a ban is implemented.
Member states also requested further evidence of links between Hizbollah and last year's bombing of a bus in Bulgaria. They were not convinced by a Bulgarian investigation into the attack.
Diplomats believe, however, that with the biggest states backing Britain's stance, it is likely the EU will eventually add Hizbollah to the list. An FCO spokesman said: "We continue to believe our evidence is robust and strong."
Meanwhile, the new Socialist-led government in Bulgaria this week backed away from the conclusion of its centre-right predecessor that Hizbollah had been behind the bus bombing.
"The evidence we have is not explicit," said Foreign Minister Kristian Vigenin, whose government took office last week.