Glenn McGrath has warned that England will not stand a chance of winning the Ashes unless James Anderson hits form.
Australia will start the series as favourites after their 5-0 win Down Under in 2013-14, despite having lost their last series in the UK.
However, McGrath has suggested that England hopes of regaining the urn will rest on Anderson's ability to swing the ball.
He told Lords.org: "Jimmy Anderson is a guy who I think will be key. He has to bowl well if England are to have any chance at all.
"He bowls well in English conditions with a Duke ball and if it's swinging he's as good as anyone around.
"If it's not swinging he doesn't seem to know what to do, which surprises me a lot. So, I think for England to have any chance at all, he has to play a big part."
McGrath took 563 Test wickets in a 14-year international career.