Bobsleigh men impress in training

John Jackson maintained hopes of Great Britain's first Olympic bobsleigh medal since 1998, topping the standings in official training.

Jackson finished 0.02 seconds behind Russia's two-man gold medallist Alexander Zubkov in the first heat of the day and improved to pip Zubkov by 0.01secs in the second.

Jackson had placed seventh and third on the opening day of official training on Wednesday.

Although a number of four-man teams use official training runs to test runners and lines, and some - including American pilot Steven Holcomb - often do not push, Jackson's times raise genuine hopes that he will be in the hunt for a medal when competition gets under way on Saturday.