Israel’s prime minister, Benjamin Netanyahu, has missed his self-imposed target date for annexation of occupied Palestinian territories, as France warned of “consequences” and Boris Johnson made an appeal to Israel to reconsider the move in an article in the Hebrew media. Johnson, who described himself in the opinion piece as a “passionate defender of Israel”, said any annexation would be a “violation of international law”, adding the UK would not recognise any changes to the pre-1967 borders in the West Bank that were not agreed by both Israelis and Palestinians. An Israeli cabinet minister and confidant of Netanyahu, Ofir Akunis, confirmed the annexation process would not begin on Wednesday, telling Israel’s Army Radio that officials were still working out the final details with their US counterparts. He insisted, however, that he still expected the annexation to take place later in July. Akunis said coordination with the Trump administration could not be dismissed. In January the US put forward a plan to bring up to a third of the West Bank under direct Israeli control and leave Palestinians with limited autonomy in pockets of the remaining land. According to sources familiar with the talks between the Trump administration and the Israelis, quoted in the Jerusalem Post, a decision on the timing and scope of annexation could take place next week. However, even as the deadline slipped, international pressure on Israel continued to escalate, with the French foreign minister, Jean-Yves Le Drian, telling a parliamentary committee that “an annexation decision could not be left without consequences”. Amid a growing debate in European capitals around retaliatory measures if Israel annexes any of the occupied territories, Le Drian added: “We are examining different options at a national level and also in coordination with our main European partners.” The United Nations, the EU and key Arab countries have all issued similar strong messages saying annexation would violate international law and undermine the already diminished prospects of establishing a viable independent Palestinian state alongside Israel. Johnson, in his article for the mass market daily Yedioth Ahronoth, emphasised his warm feelings for Israel, referencing the time he had spent working on a kibbutz as an 18-year-old, and he described his “sadness” in following the debate over annexation. Significantly, Johnson made his intervention in a piece translated into Hebrew for Yedioth Ahronoth, the country’s most widely read paid-for publication, rather than the left-leaning Haaretz or Jerusalem Post. He said he was “fearful that these proposals will fail in their objective of securing Israel’s borders and will be contrary to Israel’s own long-term interests” and “represent a violation of international law”, echoing remarks he made in parliament last month. “Annexation would put in jeopardy the progress that Israel has made in improving relationships with the Arab and Muslim world,” Johnson wrote, calling for a solution that allowed for justice and security for both Israelis and Palestinians. “I profoundly hope that annexation does not go ahead. If it does, the UK will not recognise any changes to the 1967 lines, except those agreed between both parties,” he added. The remarks from Johnson, who is seen as one of the most personally friendly European leaders towards Israel, will come as a stark reminder of the diplomatic risks involved. Under the plan announced by Trump, Israel has said it intends to extend its sovereignty to Jewish settlements and the Jordan Valley in the West Bank. However, key figures in the Trump administration – the president’s son–in–law Jared Kushner key among them – have reportedly cooled on any unilateral moves by Israel. Akunis told Israel’s Army Radio no annexation would take place until after a delayed “declaration” on the issue from Donald Trump. According to an unconfirmed report on one Israeli television channel, the Trump administration is seeking agreement for a territorial gesture towards Palestinians from Israel before proceeding. Palestinians, who have rejected the Trump proposal, want to establish a state in the West Bank and Gaza Strip, with East Jerusalem as its capital. Israel captured those areas in a 1967 war and withdrew soldiers and settlers from Gaza in 2005. Netanyahu met US envoys on Tuesday to discuss annexation within the framework of Trump’s Middle East peace plan, and said afterwards that such talks would continue for several days. A US official told Reuters: “There are very robust conversations with Israel on the Trump plan.” Trump’s proposal calls for Israeli sovereignty over about 30% of the West Bank – land on which Israel has been building settlements for decades – as well as creation of a Palestinian state under strict conditions. Palestinians say the plan would deny them a viable state. Although Netanyahu has insisted he is continuing to work with US interlocutors from the Trump administration over the timing for annexation, he has appeared increasingly isolated within his own cabinet and internationally over the proposals. Netanyahu and his senior coalition partner, Benny Gantz, are at odds over the timing of any unilateral annexation move. The plan has also attracted opposition from some settler leaders and pro-settler politicians who have voiced concern that annexation could lead to the creation of a Palestinian state, which they oppose. Johnson’s intervention, while echoing the long-held British position, is striking as he is regarded by Palestinians as unsympathetic to their cause. During a visit to the region in 2015, he was disinvited to a meeting of a Palestinian youth forum after dismissing supporters of the boycott, divestment and sanctions (BDS) movement as corduroy jacket-wearing “lefty academics”.