Footballers: Too many headers 'can damage the brain'

 Frequently heading a football can lead to brain injury, warn doctors who say they have found proof on brain scans.

Imaging of 32 keen amateur players revealed patterns of damage similar to that seen in patients with concussion.

There appears to be a safe cut off level of 1,000 or fewer headers a year below which no harm will be done, but the US investigators say more work is needed to confirm this.

Heading is believed to have killed the English footballer Jeff Astle.