Pouria Zeraati, a 36-year-old presenter at London-based broadcaster Iran International, was stabbed in the leg outside his home in Wimbledon, south London, on 29 March.

Police have said the motivation for the attack is not yet clear, but his occupation - coupled with recent threats towards UK-based Iranian journalists - meant the probe was being led by specialist counter-terrorism officers.

There have been no arrests, the Met said.

Following his discharge, Mr Zeraati thanked everyone for their calls and messages of support, posting on X: "The amount of your sympathy, kindness and love in past few days has been and is the greatest and best energy for my recovery process."

Mr Zeraati said he and his wife were living at a "safe place" under the Met's supervision.

Commander Dominic Murphy, head of the Met's Counter Terrorism Command, said the investigation was "making progress" and he was "confident" the suspects were not a risk to communities in the capital or nationally.

Iran International spokesman Adam Baillie said the Islamic Revolutionary Guards Corps (IRGC) has been targeting its broadcasters.

In October 2022 the IRGC - a key security force for the regime in Tehran - "openly" and "nakedly" warned Iran International 'we're coming for you', Mr Baillie added.

When asked about the motives behind the attack itself, he said: "We can't say. The fact that counter-terrorism is leading the investigation probably speaks for itself."

But he added that Mr Zeraati had received death threats before and that the threats against Iran International's staff had "escalated dramatically" over time.

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Since 2022, several plots to either kidnap or kill British or UK-based individuals perceived as enemies of the Iranian regime have been disrupted by police, it is understood.

Mehdi Hosseini Matin, the Iranian charge d'affaires in the UK, said "we deny any link" to the knife attack.

Iran International temporarily shut down its operations in London early last year and moved to studios in Washington after what it described as an escalation of "state-backed threats from Iran". The station resumed operations at a new location in London last September.