Bayern Munich legend Oliver Kahn fears his former club could struggle to compete with Premier League and La Liga sides if transfer fees continue to rise at their current rate.
Manchester United forked out a world-record fee of £89million to sign France international Paul Pogba from Juventus last summer, while Real Madrid and Barcelona have both spent heavily since the turn of the decade.
Javi Martinez's £34m move from Atletic Bilbao in 2012 remains Bayern Munich's record fee and Kahn fears the German champions will soon struggle to keep up with their big-spending rivals across Europe.
'Huge amounts of money will have to be spent in the war to sign the best players,' Kahn told German football magazine Socrates.