The Metro.

The Blues are keen to bolster their attacking options this summer in a bid to make a serious challenge for the Premier League title next term.

With only Fernando Torres, who has struggled since his £50m move to Stamford Bridge, and January arrival Demba Ba available as central forward options, manager Rafael Benitez hasn’t has the necessary firepower at his disposal to push the Londoners on.

This has led to speculation that they may look to draft in reinforcements, with Son high on their list of targets.

As well as Chelsea, Liverpool, Tottenham, Manchester United and Arsenal are believed to be tracking the South Korean, who has been in fine form for the Bundesliga club of late.

Radamel Falcao remains their number one target, but Roman Abramovich’s right-hand man Michael Emanalo has urged the billionaire owner to look at Son, who could open the club up to the vast Asian market.

Chelsea are keen to put themselves on a level footing with other top European clubs in the football crazy continent, and could do so b y snapping up one of the regions top stars.

Hamburg are aware they will face a fight to keep hold of the man who has netted nine goals this term, and are believed to be willing to accept around £10m for his services.