 Flaws in the proposed ?32bn High Speed 2 rail project connecting London and Birmingham could hurt the environment, according to the Institution of Engineering and Technology. Its head of policy, Paul Davies, said the case for HS2 relied on some flawed assumptions. "For example, not considering the effects of aerodynamic drag from environmental mitigation measures such as tunnels could lead to an increase in carbon emissions," he said. Engineering conglomerates are expected to be asked to bid for HS2 development in the coming weeks.