Good morning, this is Eleanor Ainge Roy bringing you the main stories and must-reads on Wednesday 2 May.

Top stories

One of Australia’s foremost lawyers, Bret Walker QC, has issued an extraordinary warning that the Murray-Darling basin plan is likely to be unlawful, because the authority overseeing it made a fundamental legal error when it set the original 2,750GL water recovery target in 2012. Walker, who is currently chairman of the South Australian royal commission into the Murray-Darling basin plan, issued the warning in a second issues paper. He also spelled out the far-reaching implications of the plan being unlawful. Not only does it mean that the original water recovery target of 2,750GL was likely was to have been set too low to deliver the environmental goal of the Water Act and could be challenged in court, but it also means that the current amendments to the plan, being debated by the Senate, are likely invalid as well.

Walker has provided a roadmap for environmental groups, or any individual affected, to challenge the plan in court and also raises the possibility that the Water Act and the Murray-Darling basin plan could be unconstitutional, because they rely on the commonwealth government’s external affairs power to enter treaties.

Donald Trump’s former campaign chairman Paul Manafort has asked a judge to investigate leaks about his case, after a list of questions that Trump could face from prosecutors, published by the New York Times, indicated authorities may have new information linking Manafort to Russia. One question stood out: “What knowledge did you have of any outreach by your campaign, including by Paul Manafort, to Russia about potential assistance to the campaign?” Most of the questions appeared to focus on whether Trump obstructed justice by interfering with the Russia investigation. Trump tweeted about the leak: “So disgraceful that the questions concerning the Russian Witch Hunt were ‘leaked’ to the media. No questions on Collusion. Oh, I see … you have a made up, phony crime, Collusion, that never existed, and an investigation begun with illegally leaked classified information. Nice!”

More than $5m was handed to a single private consultant advising the National Disability Insurance Agency, prompting renewed criticism of its spending on contractors. American global management consultants McKinsey & Company were paid $5.17m to conduct an independent review of national disability insurance scheme pricing, a major piece of work used to help determine how much people with a disability pay for support services. McKinsey & Company made 25 recommendations, all of which were adopted in-principle. Every Australian Counts, a disability advocacy group, is concerned about the amount spent on contractors. The group’s campaign director, Kirsten Deane, said nobody wanted to see the NDIA become a “big, fat bloated bureaucracy” but it clearly needed more staff.

Senior Labor Left faction players are agitated about what they see as a plan to undermine frontbencher Mark Butler’s bid to be re-elected as ALP president, with backroom claims of “trickery” snowballing. The controversy has been triggered by the late nomination of the trade union official Mich-Elle Myers. Some Left figures claim she is in the field – backed by the influential national secretary of the CFMEU, Michael O’Connor – to peel votes away from Butler. “People are angry and frustrated by this trickery,” one senior Left figure told Guardian Australia. Butler, the shadow minister for climate change, has put noses out of joint by campaigning assertively on a platform of democratising party processes.

The maker of Gibson guitars has filed for bankruptcy after diversification led to “devastating” financial falls, and debts of between US$100m-$500m. The Nashville-based company, which was founded in 1894 and employs 875 workers, said it planned to continue in the business of designing, building and selling musical instruments and equipment, including brands such as Wurlitzer, Dobro and Epiphone but it would close its arm that makes Philips headphones and other electronic accessories.

Sport

By modern AFL reckoning, clubs are either in the premiership “window”, or working to return to that exalted state with all possible speed. That’s a journey each club begins from a different place, with often very differing circumstances. As Carlton fans digest the first 0-6 season start in their club’s 121-year VFL/AFL history, many will be contemplating the finer distinctions between a rebuild and a reset – and finding neither much to their liking.

The case of Caster Semenya is complex but demanding some female athletes lower their testosterone levels was a big, wrong call, writes Andy Bull, who calls it a debatable conclusion to reach based on a questionable study.

Thinking time

Writers Vanessa Berry and Scott Bevan unveil the secret places they love in Sydney. Sydney hides the stories of its past, they say, often in plain sight, from shipwrecks to ancient trees and suburban military bunkers. Meet the anchors of Edward Lombe, the ironbark of St John’s and the Bankstown bunker.



From mindfulness to pizzas: what are the new rules for a successful work meeting? Amazon employees sit in silence – while Tesla boss Elon Musk advocates walking out if you aren’t adding value. Brevity and a phone ban could be key, but so too is the old-fashioned long lunch, with experts attesting that sharing a meal with colleagues is one the the best ways to catch up on office news. Read on for our expert guide.

Australian has more than 1 million drivers aged 75 and over. An ageing population often paired with loneliness and sporadic family support means that, for many elderly patients, driving is often a vital lifeline, and the decision to revoke the licence of an elderly driver is never an easy one, writes Ranjana Srivastava. “When an innocent driver is fatally struck by one with progressively worsening dementia, it must be morally devastating to wonder if the outcome would have been different had even one doctor raised the alarm. But an ill-considered driving ban resulting in isolation and self-harm can result in just as onerous a burden.”

Media roundup

The Australian Financial Review asks who is to blame for the cultural woes at the Commonwealth Bank, with the Australian Prudential Regulatory Authority’s investigation revealing a “widespread sense of complacency has run through CBA, from the top down”. The West Australian has the story about a 73-year-old woman found safe after being bogged in the remote mid-west bush for three days. And the ABC reports on how the work-for-the-dole CDEP scheme is harming Indigenous people, with more than 340,000 fines issued since 2015. About 80% of people on CDEP are Indigenous and live in regions with high rates of unemployment.



Coming up

The French president, Emmanuel Macron, will meet the governor general, Peter Cosgrove, and the prime minister, Malcolm Turnbull, in Sydney.

A parliamentary inquiry into religious freedom is sitting in Sydney and will hear from the Australian Catholics Bishops Conference, the Executive Council of Australian Jewry and the Anglican Diocese of Sydney along with other religious groups.

Dozens of cyclists are expected to stage a 10-minute “die-in” on the busy Vulture Street in Brisbane, designed to stop the city’s peak hour traffic and bring to attention concerns over road safety for cyclists.

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