The move, which will come into effect on Friday, subject to approval by the British parliament, criminalises anyone who is either a member of or supports the Iranian-backed group headed by Hassan Nasrallah.
Those associated with Hezbollah in the UK will face up to 10 years in prison.
“Hezbollah is continuing in its attempts to destabilise the fragile situation in the Middle East – and we are no longer able to distinguish between their already banned military wing and the political party,” Home Secretary Sajid Javid said in a statement.
“Because of this, I have taken the decision to proscribe the group in its entirety.”
Hezbollah’s military wing was banned in the UK in 2008, but the latest announcement would also place its political members – many of whom are a part of the Lebanese parliament – in the same category.
Hezbollah does not acknowledge the existence of separate wings.
Explaining its decision, the British government said the organisation continued to amass weapons in contravention of UN Security Council resolutions, while its support for Syrian President Bashar al-Assad had prolonged “the conflict and the regime’s brutal and violent repression of the Syrian people”.
“It is no longer tenable to distinguish between the military and political wings of Hizballah,” a government statement said, using a different spelling for Hezbollah.
Reacting to the announcement, Israel’s Security Minister Gilad Erdan praised the British move and urged the European Union to follow suit.
“All who truly wish to combat terror must reject the fake distinction between ‘military’ & ‘political’ wings,” Erdan said in a tweet.
Hezbollah was setup in 1982 after Israel invaded Lebanon, with the two last fighting a major war in 2006.
Last month, Lebanese politicians finally agreed to a new government, which include three Hezbollah ministers, ending an impasse that lasted eight months since the country held general elections in May 2018.
On Monday, British Foreign Secretary Jeremy Hunt said the UK staunchly supports “a stable and prosperous Lebanon” but “cannot however be complacent when it comes to terrorism”.
“This does not change our ongoing commitment to Lebanon, with whom we have a broad and strong relationship,” he added.
Andreas Krieg, a lecturer at the School of Security Studies at UK-based university King’s College London, said the British move was likely a result of “pressure coming from Washington”.
“[It is] realigning British policies with the US’ more aggressive move and policies towards containing Iran in the region,” he said.
“On the one hand, Hezbollah is a destabilising factor in the region when you look at how they are exporting their operations across Syria, Iraq and potentally also Yemen and obviously Lebanon as well, but on the other hand it is such a political player in Lebanon that it is part of the government.”
Krieg also cautioned Britain’s move could prove “counterproductive” as it would leave officials with “no wiggle room to engage” with Hezbollah.
“Coercion and hawkish approaches to the organisation … in the long run will be counterproductive because Hezbollah are where they are – they are deeply embedded in the social fabric of Lebanon,” he said.