Motor racing - Halo raises hackles as Mercedes present their new 'diva'

F1 Formula One - Mercedes 2018 Car Launch - Silverstone Circuit, Towcester, Britain - February 22, 2018 Mercedes' Lewis Hamilton, Valtteri Bottas and Executive Director Toto Wolff pose with the new car during the launch Action Images via Reuters/Matthew Childs

SILVERSTONE, England (Reuters) - Formula One champions Mercedes launched their 2018 car on Thursday with team boss Toto Wolff hoping it proved less temperamental than the last one and admitting he would like to attack it with a chainsaw.

The Austrian, whose team have won the last four championships and are favourites for a fifth with Lewis Hamilton, is no fan of the mandatory new 'halo' head protection device.