Donald Trump has significantly escalated his criticism of UK Prime Minister Keir Starmer, specifically regarding the United Kingdom's initial reluctance to immediately support US-Israeli strikes on Iran. Trump, using his social media platform, remarked on the UK's consideration of sending aircraft carriers to the Middle East, stating, "That’s OK, Prime Minister Starmer, we don’t need them any longer – But we will remember. We don’t need people that join Wars after we’ve already won!" This sharp rebuke followed the UK's decision to allow US forces to utilize bases in Fairford, Gloucestershire, and Diego Garcia in the Indian Ocean for "specific and limited defensive purpose," a reversal from an earlier refusal.

The UK Ministry of Defence confirmed that four US bombers had landed at a Royal Air Force base in Britain on Friday and Saturday, already commencing operations from these British bases to prevent Iranian missile firings, which were deemed to be putting British lives at risk. Concurrently, British officials initiated preparations for the aircraft carrier HMS Prince of Wales for potential deployment to the Middle East, citing its very high readiness and efforts to reduce its deployment time amidst rising tensions stemming from the US-Israel and Iran conflict. Within the UK, members of Starmer’s Labour party have expressed caution regarding military involvement, with critics suggesting the Prime Minister is prioritizing domestic electoral concerns over the traditional "special relationship" with the United States.

From the US perspective, Secretary of State Marco Rubio, speaking at a regional security conference in Miami, offered a veiled critique of the UK and other nations like Spain that had initially refused base access for strikes on Iran. Rubio emphasized the importance of allies being present when needed, stating, "At a time when we have learned that an ally, when you need them, may not be there for you, these are countries that have been there for us," adding, "We want you to see that when you are a friend and ally to the United States, it is a good thing and it is reciprocated back the other way."

Concurrently with these diplomatic and military developments, thousands of protesters gathered in central London, marching to the US embassy to demand an end to US and Israeli strikes on Iran. The demonstration on Saturday afternoon was led by various groups including the Campaign for Nuclear Disarmament (CND), Stop The War, the Palestine Solidarity Campaign, the Muslim Association of Britain, the Palestinian Forum in Britain, and Friends Of Al-Aqsa, commencing from Millbank near Westminster.

Protesters displayed a strong visual presence, carrying Iranian and Palestinian flags, alongside portraits of Iran’s former supreme leader, Ayatollah Khamenei, who, according to protest information, was killed in the opening strike of the war last Saturday. Placards carried messages such as “Stop Trump’s Wars,” “Stop the War on Iran,” “Stop Arming Israel,” and “No War on Iran,” clearly articulating their anti-war stance.

Outside the US embassy in Vauxhall, Your Party MP Zarah Sultana addressed the crowd, invoking the memory of the 2003 US-led invasion of Iraq. She highlighted the false pretenses of that war, specifically the claims of weapons of mass destruction and promises of peace and democracy that proved to be vastly different from reality. Sultana declared, "We will not be ignored again," and urged attendees to raise their voices for peace, justice, and a world where governments learn from past lessons.

A statement from former Labour leader Jeremy Corbyn, who could not attend, was read to the assembled crowd. In it, Corbyn, now an independent MP, echoed Sultana's sentiments by recalling the protests against the "illegal invasion of Iraq" in 2003, stating, "we were ignored, but we are here today to say loudly and clearly: do not drag Britain into another illegal war." He advocated for a foreign policy rooted in cooperation, equality, and sovereignty, rather than one blindly following the US in "catastrophic interventions," emphasizing that "forever war is not a game" and holding the US and Israel accountable.

According to a police officer present, between 5,000 and 6,000 protesters participated in the march from Millbank to the US embassy. The Metropolitan Police reported one arrest for suspicion of inciting racial hatred in relation to a placard, followed by three further arrests for possession of an offensive weapon, racially aggravated public order offences in relation to a chant, and violent disorder from an incident the previous day. Police had increased patrols and imposed conditions on the protest route and rally finish time. During the march, groups holding Israeli flags stood on the side of Millbank, leading to exchanges of shouts between them and the anti-war protesters, with epithets like “shame on you” and “murderers” being exchanged.

Protesters articulated their personal motivations for attending. Daniela Costa, a 30-year-old Brazilian student residing in London, expressed solidarity with Iran, Palestine, Cuba, and Venezuela, hoping the protest would signal to the UK government its lack of popular support for any involvement in the war, including providing weapons or military bases. Martin Perry, 58, from Northampton, stated his attendance was driven by the belief that acts against Iran violate international law, and he aimed to convey to Keir Starmer that the public opposes war against Iran and involvement in any illegal conflict. Organizers also announced a future "march against the far right" scheduled for 28 March in central London.