Good morning, this is Helen Sullivan bringing you the main stories and must-reads on Tuesday 25 June.

Top stories

The Morrison government’s tax plan to tackle “bracket creep” will give more compensation to income earners who need it the least, a new analysis of Australia’s tax system has found. The Australia Institute reviewed 18 years of tax policy and found wage earners at all levels had been overcompensated for bracket creep, with income tax cut by larger amounts than the tax increased owing to moving up a bracket. Including the government’s planned flat tax of 30% for people earning between $45,000 and $200,000, the thinktank estimates someone earning $60,000 would be $1,919 a year better off compared with if tax thresholds had just been increased to account for inflation. But someone on $125,000 would be $7,035 a year better off and someone on $200,000 was $19,785 better off.

Donald Trump has ordered new sanctions against Iran’s supreme leader, Ali Khamenei, in the latest step of an escalating campaign against Tehran. Sanctions have also been issued against eight Revolutionary Guard commanders. Iran’s foreign minister, Javad Zarif, will face fresh sanctions in a few days, US officials said. Signing an executive order, Trump called the increased sanctions “hard-hitting”, saying they would deny the supreme leader, his office and and those closely affiliated with him access to key financial resources.

Cocaine and methamphetamines are fuelling crime and chaos in Fiji, as the Pacific island nation grapples with a growing drug problem. Law enforcement says increased domestic drug use in Fiji, as well as in other Pacific nations such as Tonga and Samoa, has been fuelled by a combination of factors: growing economies, booming tourist industries and the fact these countries lie on a transnational drug-shipping route used by traffickers to bring cocaine and methamphetamines from the US and Latin America to Australia and New Zealand. Last May a fisherman in Papua New Guinea found $50m worth of cocaine buried in sand. Within two weeks, his chance find would lead to his remote community being threatened by a drug gang, a week-long open-ocean police boat chase, a booby-trapped fishing vessel running aground on a reef and the disappearance of the huge cocaine haul.

World

Facebook Twitter Pinterest The newly elected mayor of Istanbul, Ekrem İmamoğlu, celebrates his win. Photograph: Onur Gunal/AFP/Getty Images

All eyes are on Turkey’s President Recep Tayyip Erdoğan after his party lost the mayoral election in Istanbul. The result has serious financial implications for the ruling Justice and Development party and its patronage networks, and will amplify the sense that the president’s power may be starting to wane.

British Conservatives have stepped up warnings that a Boris Johnson premiership could lead to the collapse of the government if the leadership frontrunner attempts to pursue a no-deal Brexit.

E Jean Carroll has said she is considering bringing a complaint to the New York police department. The celebrated advice columnist has accused Donald Trump of sexually assaulting her in the mid-1990s.

An unprecedented week-long heatwave is beginning its advance across continental Europe. Meteorologists said temperatures would reach or even exceed 40C from Spain to Switzerland, as hot air was sucked up from the Sahara by the combination of a storm stalling over the Atlantic and high pressure over central Europe.

Nasa’s Curiosity rover has detected its largest belch of methane on Mars so far, exciting scientists and fuelling speculation that the robot may have trundled through a cloud of waste gas released by microbial Martians buried deep under the surface.

Opinion and analysis

Facebook Twitter Pinterest ‘For many of us, his elevation will signal Britain’s abandonment of any claim to be a serious country.’ Photograph: Peter Summers/Getty Images

“I was Boris Johnson’s boss: he is utterly unfit to be prime minister,” writes Max Hastings, the former editor of the Daily Telegraph and London Evening Standard. “It would be fanciful to liken the ascent of Boris Johnson to the outbreak of global war, but similar forces are in play. There is room for debate about whether he is a scoundrel or mere rogue, but not much about his moral bankruptcy, rooted in a contempt for truth. Nonetheless, even before the Conservative national membership cheers him in as our prime minister – denied the option of Nigel Farage, whom some polls suggest they would prefer – Tory MPs have thronged to do just that.”

Last week for the first time the Australian government two-year and three-year bonds fell below 1% and, on Friday, so too did the yield for five-year bonds, writes Greg Jericho. “I know bond yields are not the sexiest of subjects … but they give us a good insight into where the economy is likely heading.” And it isn’t good, writes Jericho: “They also put paid to any hogwash that the government could rightly have claimed during the election campaign that the fundamentals of the economy were strong.”

Sport

Ashleigh Barty has pulled out of Eastbourne with longstanding shoulder problem. The French Open champion, having the season of her life with three titles and 35 wins from 41 matches, said she was taking no chances with the flare-up and expected to be fully fit for Wimbledon next week.

When England play Australia at Lord’s on Tuesday, there are a few questions that will need answering,” writes Geoff Lemon. “For England’s part, whether they will flourish or falter when the pressure really starts to build. For Australia’s, whether this current team can really mount a credible challenge for the trophy.”

Thinking time: the native Australian plants facing extinction

Facebook Twitter Pinterest There are only 500 matchstick banksia left in the wild at 11 different sites. Photograph: Andrew Crawford/Threatened Species Recovery Hub

Humans are devastating the world’s plants and causing a “frightening” number of extinctions, according to a global scientific survey of the issue. This is certainly the case in Australia, where plants make up 72% of the total threatened species list. This accelerating decline in the world’s biodiversity will have grave consequences for human society, as the UN’s global assessment report found.



Research by the Threatened Species Recovery Hub listed the 100 plants that are most at risk, threatened by urbanisation, inappropriate fire regimes, introduced plant disease and habitat loss. “The good news is that every one of the species on the list can be saved – we have the techniques required, we just need the commitment,” said a researcher, Dr Rod Fensham from the University of Queensland. Our interactive guide allows you to explore the types of plants at risk, the regions at risk and the major threats, with an example for each category.

Media roundup

The Sydney Morning Herald leads with the headline Minister signals shakeup for super, with Jane Hume saying she doesn’t think the government “can morally ask workers to give up more of their current earnings and put them into an inefficient system”. The Australian calls Scott Morrison’s tax cut “an ultimatum for senators”, as the PM “moves to ­ensure the Senate sits without a break until the Coalition’s entire $158 billion income tax cut package is passed when parliament resume­s next week”. And killer whales in WA have Australian accents, the ABC reveals.

Coming up

More than 150 religious leaders from across Australia will issue an open letter calling on Scott Morrison to recognise Australia’s “moral responsibility to avoid climate catastrophe”.

The shadow treasurer, Jim Chalmers, will deliver his first major speech since taking on the role after the election at the National Press Club.

Sign up

If you would like to receive the Guardian Australia morning mail to your email inbox every weekday, sign up here.