Fiscal headroom is a matter of guesswork | Brief letters

Your editorial (The Guardian view on OBR v the Treasury: ministers have embraced the theatre of errors, 1 December) correctly flags the huge uncertainty in trying to come up with a five-year forecast of the difference between taxes and spending. Although markets like big fiscal headroom numbers, they seem to ignore the wise words of Bertrand Russell, who defined mathematics as “the subject in which we never know what we are talking about, nor whether what we are saying is true”. This also applies to the concept of the medium-term fiscal headroom that economists and politicians alike are obsessed with.Prof Costas MilasUniversity of Liverpool The scrapping of the two-child benefit limit certainly seems to have polarised opinion. One camp reckons it should not have been scrapped at all, and the other reckons it should have been done a year ago

OBR chief’s exit may ease pressure on Rachel Reeves but the battle isn’t over

Had Richard Hughes not resigned as boss of the Office for Budget Responsibility (OBR) on Monday amid the indignation over the accidental publication of Rachel Reeves’s budget, the Treasury might now be under pressure over the tsunami of leaks that preceded it.The OBR’s David Miles told MPs on Tuesday the leaks had been so widespread and misleading that the watchdog feared its reputation was at stake.Alongside briefings about the potential direction of OBR forecasts, there were public comments too, including from Reeves herself, about the frustrating timing of the watchdog’s productivity rethink; and its refusal to “score” pro-growth policies.Arguing for an ambitious “youth experience scheme” in September, for example – details of which are still to be negotiated – the chancellor told the Times, “we want the OBR to score it. They scored it when we left the European Union

The fight to see clearly through big tech’s echo chambers

Hello, and welcome to TechScape. I’m your host, Blake Montgomery. Today, I’m mulling over whether to upgrade my iPhone 11 Pro. In tech news, there’s a narrative battle afoot in Silicon Valley, tips on avoiding the yearly smartphone upgrade cycle and new devices altogether, and artificial intelligence’s use in government, for better and for worse.The encroachment of technology can feel inevitable

‘The biggest decision yet’: Jared Kaplan on allowing AI to train itself

Humanity will have to decide by 2030 whether to take the “ultimate risk” of letting artificial intelligence systems train themselves to become more powerful, one of the world’s leading AI scientists has said.Jared Kaplan, the chief scientist and co-owner of the $180bn (£135bn) US startup Anthropic, said a choice was looming about how much autonomy the systems should be given to evolve.The move could trigger a beneficial “intelligence explosion” – or be the moment humans end up losing control.In an interview about the intensely competitive race to reach artificial general intelligence (AGI) – sometimes called superintelligence – Kaplan urged international governments and society to engage in what he called “the biggest decision”.Anthropic is part of a pack of frontier AI companies including OpenAI, Google DeepMind, xAI, Meta and Chinese rivals led by DeepSeek, racing for AI dominance

Mike Tomlin says Pittsburgh Steelers fans are right to boo his team

Pittsburgh Steelers head coach Mike Tomlin says fans who booed the team during their 26-7 loss to the Buffalo Bills on Sunday are in the right.“In general, I agree with them, from this perspective: Football is our game, we’re in a sport entertainment business,” Tomlin said Tuesday. “And so if you root for the Steelers, entertaining them is winning. And so when you’re not winning, it’s not entertaining.”The Steelers are tied at the top of the AFC North and have never endured a losing campaign in Tomlin’s 18 full seasons in charge

Strengthened Australia welcome England to Gabbatoir in pivotal Ashes week | Ali Martin

My first day at the Gabba was 23 years ago, half a lifetime having passed since I slept on my brother’s sofa across the river and followed the Ashes tour as a backpacker. The coin went up, Nasser Hussain decided to have a bowl, and Steve Waugh’s Australians cashed in on generosity.Having not returned until 2017‑18, and then covered the Covid tour four years later, the Sydney finale in 2003 remains the only time I have seen England win a Test on Australian soil. Even then I missed the last day: flat broke and forced to head back to Queensland to find work, I eventually found myself on a farm upstate, shovelling melons like a scrum-half for eight hot hours a day while dodging venomous snakes underfoot.It was three dollars to the pound back then, but the main difference before the tour started was expectation