How have McLaren improved so quickly? 'It didn't happen overnight'

This season McLaren have been labelled as having the 'fastest car on the grid', as they now sit seven points behind Ferrari in the Constructors. They have introduced a range of upgrades to their car already this season, which has rewarded them with consistent points scoring by at least one of their drivers. However, former McLaren mechanic Marc Priestley, who spoke exclusively to GPblog, via LordPing, has explained that this success has not happened overnight.