Michelle Cound shows off Chris Froome sunburn on Twitter

Team Sky is renowned for its 'marginal gains' philosophy, a term coined by team principal Sir Dave Brailsford, who looks at the most minute details to enhance chances of success.

The mesh jersey Froome was wearing was created to meet the needs of the riders for maximum cooling and minimum weight on the hottest mountain days.

However, that means the treatment Rapha uses on its regular race jerseys - to reflect the sun - cannot be used on the mesh jerseys...so sun protection must be worn.

We'd suggest max factor, Chris.