Nicola Sturgeon, Scotland's first minister, has written to Boris Johnson to ask for the transfer of legal powers to the Scottish government to hold a second independence referendum, as she described the SNP’s success in last week’s general election as an 'unarguable mandate by any normal standard of democracy'.

Sturgeon confirmed on Thursday morning that she had formally made the request as she published a document setting out the 'clear democratic case for transfer of powers'