Panorama: The Most Dangerous Woman in Britain?

She has been called 'The Most Dangerous Woman in Britain'. Nicola Sturgeon's party is riding high in Scotland, sending a tartan army of MPs to Westminster, but what will the SNP's electoral success mean for the rest of the UK? Panorama goes behind the scenes with Scotland's first minister to investigate the rise to power of the woman who holds the future of the union in her hands.