Chelsea told to stump up £35m for Lewandowski as Dortmund stand firm.

Chelsea have been told they must double their offer if they want to prise Robert Lewandowski away from Borussia Dortmund.

The European champions are understood to have made an initial offer of £13million rising to £17m for the Poland striker, 23, who has two years left on his contract.

Chelsea are considering alternatives to Napoli’s  expensive Edinson Cavani, yet Dortmund value Lewandowski closer to £35m.

Tottenham, Arsenal and Manchester United are also interested in Lewandowski. His representative Maik Barthel said: ‘A £13m transfer fee is not suitable