Seventies progressive rock band Yes have cancelled  a reunion tour to mark their 40th anniversary after front-man Jon Anderson was diagnosed with acute respiratory failure.

Anderson was admitted to hospital last month after a severe asthma attack and doctors have advised him to rest for the next six months or face further respiratory problems.

The band was last reformed for a successful World tour in 2002, and Anderson and Rick Wakeman have also toured together as recently as 2006.

This summers tour would have featured Oliver Wakeman on keyboards after his father Rick had already taken doctors advice to pull out.