Last modified on Wed 5 May 2021 08.50 EDT
Anti-independence campaigners have spent tens of thousands of pounds in the past week calling for tactical voting to prevent the Scottish National party winning a Holyrood majority.
At least five pro-UK groups have bought newspaper adverts, mobile ad vans and electronic billboard sites, and numerous adverts on Facebook, urging voters to support election candidates most likely to beat an SNP candidate.
Scotland Matters, a group co-founded by Prof Hugh Pennington, a bacteriologist in Aberdeen who rose to prominence during E coli food poisoning outbreaks in the 1990s, registered with the Electoral Commission so it can spend up to £75,000 on tactical voting adverts during the election.