The London club also have an option to sign the 20-year-old on a permanent basis at the end of the season, according to their official website.

Barnes, who has represented England at both under-18s and under-19s level, came to the fore as a teenager in the Rams' promotion season in 2006/07. But an injury in the Coca-Cola Championship play-off final meant he played a reduced role in their Premier League campaign.

He scored twice against Manchester United in the Carling Cup semi-final earlier this month and now has another chance to establish himself in the top flight.