Five Syrian terror organisations, including Isis, the al-Qaida affiliate behind the current insurgency in Iraq, are to be banned in Britain.

The move comes as the foreign secretary, William Hague, told MPs that as many as 400 British jihadists could be fighting with Isis in Iraq. There are fears that some could return to Britain as battle-hardened radicals.

A Home Office proscription order to be approved by parliament this week will make it illegal to be a member of or to provide support to the Islamic State of Iraq and the Levant, known as Isis.

Home Office officials said that the move was triggered by the jihadist organisation's actions in Syria but developments in Iraq had underlined the need to ban the group in Britain.

The four other groups linked with Syria that also face being banned in the UK are Türkiye Halk Kurtulus Partisi-Cephesi, also known as the Turkish People's Liberation Party or the Hasty Ones; Kateeba al-Kawthar; Abdallah Azzam Brigades, including the Ziyad al-Jarrah Battalions; and the Popular Front for the Liberation of Palestine – General Command.

Security minister James Brokenshire said: "We condemn all acts of terrorism committed in Syria, where the conflict poses a growing threat to the UK, regional and international peace and security. Proscription is a useful weapon in the armoury at the disposal of the government, police and security service to disrupt terrorist activity and protect the UK."

He added: "We want to send a strong message that terrorist activity is not tolerated wherever it happens."

Downing Street said last week that the security services were monitoring very closely the possibility that British jihadists fighting in Syria could be among Isis fighters that have crossed the border into Iraq.

One thinktank, the Quilliam Foundation, has also warned that British jihadists in Syria are likely to be keen to join Isis because of the huge gains they have made in Iraq in the last few days.