GlaxoSmithKline, the UK-based pharmaceutical group, is opening its portfolio of experimental drugs to external scrutiny in a radical shake-up designed to develop more successful medicines.

In an effort to replicate the creativity of start-up drug companies, Andrew Witty, the new chief executive, will split researchers into much smaller teams. They will compete for $1bn (£500m) a year in funding from a panel including a venture capitalist and the chief executive of a biotechnology company.