Britain's interior minister Priti Patel on Friday said she had banned Palestinian group Hamas in a move that brings the UK's stance on Gaza's rulers in line with the United States and the European Union.
"Hamas has significant terrorist capability, including access to extensive and sophisticated weaponry, as well as terrorist training facilities," Patel claimed in a statement.
"That is why today I have acted to proscribe Hamas in its entirety."
The organisation would be banned under the Terrorism Act and anyone expressing support for Hamas, flying its flag or arranging meetings for the organisation would be in breach of the law, the interior ministry confirmed. Patel is expected to present the change to parliament next week.
Founded in 1987, Hamas opposes the existence of Israel and peace talks, instead advocating "armed resistance" against Israel's occupation of the Palestinian territories.
Until now Britain had banned only its military arm — the Izz al-Din al-Qassam Brigades.
Hamas political official Sami Abu Zuhri said Britain's move showed "absolute bias toward the Israeli occupation and is a submission to Israeli blackmail and dictations".
"Resisting occupation by all available means, including armed resistance, is a right granted to people under occupation as stated by the international law," said Hamas in a separate statement.
The Palestinian Mission to the United Kingdom, which represents President Mahmoud Abbas's Western-backed Palestinian Authority, also condemned the move.
In 2017, Patel was forced to resign as Britain's international development secretary after she failed to disclose meetings with senior Israeli officials during a private holiday to the country, including then-opposition leader Yair Lapid.
Lapid, now Israel's foreign minister, hailed the decision on Hamas as "part of strengthening ties with Britain".