Mohammad Sarwar, a former Labour MP, posted a tribute to Ayatollah Ali Khamenei, pictured at top of page, describing his death in a joint US and Israeli strike at the weekend, as a “martyrdom”.
Attacks were launched following the breakdown of talks on the country’s nuclear activities, sparking missile and drone strikes across the region.
Anas Sarwar described the ruling Iranian regime as “brutal” and said it was a threat to the UK.
In posts on social media Mohammad Sarwar, who has also been a governor or Punjab in Pakistan, described the ayatollah’s death as a martyrdom which had “left hearts in grief”.
He claimed the worldwide community of Muslims had lost “a strong voice of resistance”, adding: “May Allah the Exalted grant him paradise of the highest degree.
“We share equally in the sorrow of the Iranian nation.”
The ayatollah’s death has been met with both mourning and celebrations inside Iran.
Anas Sarwar, speaking to reporters in Glasgow, said: “I’m a 42-year-old man, ask me my view not what the old man’s view is.
“I’m really clear that the Iranian regime is a brutal regime – brutal with its own people.
“It’s a threat to its neighbours, it’s a threat to us in the UK.”
The Scottish Labour leader called for a de-escalation of the conflict and for the Iranian people to decide their own future, adding that he had not spoken to his father since he posted the tribute to Khamenei.
Prime Minister Sir Keir Starmer said on Sunday that US forces would be allowed to operate from British bases against Iran, but only in a limited role targeting missile sites.
Sarwar, who has called for the prime minister to resign, said the UK had a “duty to make sure we are protecting our allies, protecting our infrastructure, protecting our citizens in these nations and beyond”.
He added that the UK should support defensive – but not offensive – military action.
Mohammad Sarwar, who became Britain’s first Muslim MP in 1997, stepped down from Westminster in 2010, with his son later elected in his place.
Originally from Pakistan, he came to the UK in the early 1970s and became a millionaire through his cash-and-carry business.
After stepping back from UK politics he served two terms as governor of Punjab in Pakistan.