Benjamin Netanyahu has met Boris Johnson in London as part of a drive to discourage world powers from dialogue with Iran.

The Israeli prime minister was in Downing Street with his preoccupied British counterpart on Thursday for 29 minutes, but speaking ahead of the substantive discussions, Netanyahu said he wished to discuss Iran and Johnson voiced his support for a two-state solution to the Israeli-Palestinian conflict.

Netanyahu praised Johnson for his “staunch stance against antisemitism and ... support for Israel’s security”. A Downing Street spokesperson later said the two leaders “agreed on the need to prevent Iran getting a nuclear weapon and stop wider destabilising Iranian behaviour”, while Johnson “stressed the need for dialogue and a diplomatic solution”.

Netanyahu wants the UK to spurn a French plan to offer a $15bn (£12bn) credit line to help Iran sell oil.

Johnson also met the US vice-president, Mike Pence, while Netanyahu was to hold talks in London later in the day with the US defence secretary, Mark Esper. That Johnson cleared his diary in the middle of domestic political chaos is a mark of Netanyahu’s influence in Downing Street.

Iran and three European countries – Britain, France and Germany – have been engaged in talks to save the landmark 2015 nuclear accord, which has been unravelling since Donald Trump withdrew from it in May last year.

On his way to London the Israeli leader cited an Iranian plan to restart research on building advanced nuclear centrifuges as a further breach of the accord. The centrifuge plan, Tehran’s third step away from the deal, was announced by the Iranian president, Hassan Rouhani, on Wednesday.

In its first response to the Iranian decision, the Foreign Office said: “Iran’s plan … is deeply concerning. This third step away from its commitments under the nuclear deal is particularly disappointing at a time when we and our European and international partners are working hard to de-escalate tensions with Iran.”

Netanyahu said: “This is not the time to hold talks with Iran. This is the time to increase the pressure on Iran. These are important matters for the state of Israel at all times, but especially now.”

Q&A What is the Iran nuclear deal? Show In July 2015, Iran and a six-nation negotiating group reached a landmark agreement known as the Joint Comprehensive Plan of Action that ended a 12-year deadlock over Tehran’s nuclear programme. The deal, struck in Vienna after nearly two years of intensive talks, limited the Iranian programme, to reassure the rest of the world that it cannot develop nuclear weapons, in return for sanctions relief.

At its core, the JCPOA is a straightforward bargain: Iran’s acceptance of strict limits on its nuclear programme in return for an escape from the sanctions that grew up around its economy over a decade prior to the accord. Under the deal, Iran unplugged two-thirds of its centrifuges, shipped out 98% of its enriched uranium and filled its plutonium production reactor with concrete. Tehran also accepted extensive monitoring by the International Atomic Energy Agency (IAEA), which has verified 10 times since the agreement, and as recently as February, that Tehran has complied with its terms. In return, all nuclear-related sanctions were lifted in January 2016, reconnecting Iran to global markets. The six major powers involved in the nuclear talks with Iran were in a group known as the P5+1: the UN security council’s five permanent members – China, France, Russia, the UK and the US – and Germany. The nuclear deal is also enshrined in a UN security council resolution that incorporated it into international law. The 15 members of the council at the time unanimously endorsed the agreement. On 8 May 2018, US president Donald Trump pulled his country out of the deal. Iran announced its partial withdrawal from the nuclear deal a year later. Saeed Kamali Dehghan, Iran correspondent

There is suspicion that Netanyahu’s lightning visit to London is in part designed to bolster his international standing and play the security card before highly charged elections in a fortnight.

The timing also gives him a platform to pour cold water on a proposal from the French president, Emmanuel Macron, that has already been greeted with deep scepticism by the US special representative on Iran, Brian Hook.

Donald Trump has reiterated his willingness to meet Rouhani, but said there would be no easing of US sanctions. “That’s not happening,” he said. “That won’t be happening.”

It would be a diplomatic coup for Israel and the US if they could lever Britain away from the Macron plan, and even more so away from the nuclear deal. London has so far resisted a year of pressure from the White House, and has stood alongside France and Germany, the two original signatories to the 2015 deal. The three countries insist that Iran had not breached the deal, and that it remained the best way to prevent nuclear proliferation in the region.

Many European diplomats say the narrowing door to diplomacy remains open because Iran has announced it will take its next step on centrifuges only if, in two month’s time, no progress on selling oil has been made. Iran also did not announce any steps to increase its level of uranium enrichment.

France proposes a $15bn credit line as a prepayment for the purchase of Iranian oil, but the plan requires US willingness to reinstate sanctions waivers on countries that purchase Iranian oil. The credit line would be the first step in a phased programme to address wider concerns with Iran, including its ballistic missiles and regional behaviour. Britain has not yet said anything publicly in support of the plan, emphasising instead that it has been led by the French.

Given the US and Israeli approach, however, Macron’s chances of success seem to be receding. Rouhani has also refused to countenance a meeting with Trump, and the Iranian decision on centrifuges has disappointed the French.

Netanyahu did not rule out such a meeting. “Obviously, I don’t tell the US president when to meet or with whom,” Netanyahu said. Responding to the suggestion that his brief visit was designed to boost his electoral appeal, Netanyahu said: “Those delusional claims are a lie. I don’t profiteer with our security.”

In a step away from confrontation, the owner of the captured British-flagged ship Stena Impero has confirmed that the Iranian authorities have released seven crew members.

In a separate development, US officials said on Thursday that Jason Greenblatt, Trump’s special envoy for the Middle East, planned to resign once the long-delayed US peace plan for Israel and Palestine is released.