Labour’s shadow international development secretary has unexpectedly backed intervention in Syria and called for Bashar al-Assad to be removed as president.

As Britain gears up to support the US in strikes against the Assad regime, Kate Osamor insisted “intervention must take place” if evidence suggests government forces used chemical weapons against civilians. She also said the Syrian president “needs to be removed”, although she admitted “it’s not as easy as that”.

Her backing for intervention came as her party leader, Jeremy Corbyn, said he did not support further British military action in Syria.

Ms Osamor suggested Mr Corbyn should stop making statements on foreign policy and instead leave the job to his shadow ministers.

In an outspoken interview with The House magazine, the Edmonton MP also suggested Labour could support a boycott of Israel, which she compared to apartheid South Africa, and said Prince Charles should not be allowed to succeed the Queen as head of the Commonwealth.

Her comments on Syria are unlikely to be welcomed by Mr Corbyn, who has emphasised the need for a “political solution” to the war and said he is against “increasing military action”, which he warned “could escalate the conflict beyond belief”. Labour has said parliament must be allowed to weigh up the evidence and vote on the issue before the UK launches any strikes.

While Ms Osamor, an ally of Mr Corbyn, did not specifically endorse military action, the Labour frontbencher’s call for “intervention” will come as a boost to Theresa May as she attempts to persuade her Cabinet, and then parliament, to back air strikes against the Assad regime. A spokesperson for Ms Osamor said she had been referring to non-military intervention.

Asked about reports that forces loyal to the Syrian president had used chemical weapons against civilians in the town of Douma, Ms Osamor said: “That person needs to be removed. I mean, intervention must take place if evidence comes back that the PM or the president or whoever the leader is, is gassing his own people. Get them out.

“But I suppose what we’ve seen is it’s not as easy as that. And I think that’s where Jeremy’s position comes from. It’s not as easy as just removing someone.”

She added: “I think that’s what needs to happen. They always seem to abscond, end up in another country. This world is messed up. It’s not easy. But if a leader is killing their own they need to be removed. We don’t keep them there. They need to go. He needs to be removed.

“But how do you remove someone? I’m saying this almost as a layman, but I know politically you can’t just remove somebody who is elected.”

A spokesperson for the shadow international development secretary said: “Kate was expressing her horror at the chemical attack in Douma and the terrible suffering of the Syrian people in the conflict.
 
“She recognised that there is no simple solution to bringing about lasting peace in Syria, which is why there must be an urgent coordinated international drive via the UN to achieve a ceasefire, a negotiated political settlement and the right of the Syrian people to determine their own future.”

Ms Osamor also suggested Mr Corbyn should stop making statements on foreign policy in place of herself or Emily Thornberry, the shadow foreign secretary.  

The Labour leader personally responded to the killing of Palestinian protesters by Israeli forces in the Gaza Strip, but eyebrows were raised when, days later, a Labour statement on the alleged use of chemical weapons in Syria was issued from an unnamed spokesperson, although Mr Corbyn also tweeted about the issue.

Asked about her party leader’s comments on Gaza, Ms Osamor said: “First and foremost, he should allow the spokesperson for that department really to respond. It’s not that he shouldn’t have said it, but if that’s what he’s being assessed on – that’s what he’s being judged on – then he should just let his spokesperson speak because it seems that whatever he says is not good enough – it’s too strong or it’s not strong enough.

“When actually, he’s the leader. So, it should be Emily or me, whoever, should be responding. And maybe that’s what he should do.”

She added: “It’s much more serious than whether or not Jeremy has made a statement or not. It’s about the fact that this has taken place and what are the government doing.

“We don’t want this to be about the British media and Jeremy, which it has become, as opposed to that people are being gassed, people are being shot or whatever and the government has decided this is what they need to do.”

Discussing the situation in Israel in more detail, Ms Osamor said Labour could ultimately support a boycott of the Jewish state, although she claimed “educating people” on the issue should be the party’s focus.

“I think we need to open up the debate before we start saying what we should be doing,” she said. “Unfortunately, a lot of people are not really educated on illegal settlements, people don’t understand what’s really going on, and it’s gone over their head. [They say] ‘It’s BDS, who cares, what’s that got to do with anything?’

“But I think we need to get to a place where we start educating everybody and make a decision based on that and then say, ‘this could be an alternative, this could be an option’.

She added: “I would not say at this point in opposition we should be planning around boycotting without educating a whole generation that have missed out on that and don’t understand what’s going on.

“There’s a level of education that needs to take place first and I would more be an advocate of that than actually worrying about BDS or not because a lot of people aren’t educated and haven’t made a decision based on that.”

Labour’s deputy leader, Tom Watson, has previously said calls for widespread boycotts, sanctions and disinvestment of Israel are “morally wrong”. Asked about that claim, Ms Osamor said: “Sometimes people make statements but then they don’t look about the history around apartheid, around separation, around people living side by side.

She said a boycott of apartheid South Africa “did make a difference” and called on people not to buy products from Israeli settlements in the Occupied Territories.

Ms Osamor was speaking ahead of a major meeting of Commonwealth heads of government in London next week.

She used the occasion to suggest Prince Charles should not succeed the Queen as head of the institution.

She said: “I don’t particularly think it should be him. Not because I have an issue with the royal family. I just don’t think it should be him. I don’t really know what he’s been up to of late. He’s not been that vocal on issues.

“But we just need someone who’s level-headed, someone people respect but also someone who thinks outside the box.”  

Speaking to the same magazine, Ms Thornberry called on the UK government to apologise to the Commonwealth and to the Queen for Margaret Thatcher’s refusal to take a tougher stance against apartheid South Africa in the 1980s.

Ms Thornberry said: “Back then, it was nothing less than our duty to take part in collective action against South Africa, and heed the urgent calls from our Commonwealth partners for the unified imposition of sanctions. But instead, the Thatcher government dismissed them.

 “I believe Theresa May and the Conservative government in Britain also owe an apology to the Commonwealth as a whole – and indeed Her Majesty The Queen – for ignoring the efforts of every other member thirty years ago to bring Apartheid to an end.”