SNP spin doctors have issued advice to Scottish broadcasters on how to ensure that Tories are “tied in knots” over their opposition to a second independence referendum.

An email sent to senior journalists and seen by The Times urges television and radio reporters to “rigorously” scrutinise Conservative politicians when they state their opposition.

The note cites an interview by Bernard Ponsonby, the STV correspondent. He took the Tory economy spokesman Dean Lockhart to task for claiming that Boris Johnson had a mandate to deliver Brexit by delivering a majority of MPs while arguing that there should not be a second referendum because the SNP won less than 50 per cent of the vote in Scotland.

“Bernard Ponsonby highlights how easily Tories — who try