As a general rule I really don’t like surveys on things like tactical voting because we are asking a pollster to do something that’s highly complicated and we should retain our sectptism.
A concern on the polling above is that members of the YouGov panel might have a tendency to be more politically involved than the norm and therefore, possibly, more likely to state that they would use their vote in a tactical way.
The first polling to feature in the panel above seeks to find out what LAB and GRN voters would do in seats where the Tories are slugging out with the LDs. The second panel seeks to established what LD voters voters would do where the battle in their seat is perceived to be between Labour and the Tories.
One danger is that these are based on perceptions of the likely main battle in each seat and things might have changed dramatically since baseline of GE2017. LAB has lost a lot of support as have the Tories. The LDs, meanwhile, have seen their polling shares get to nearly three times the last general election level. There might be what in 2017 were CON-LAB marginals where the LDs would now fancy their chances.
On the basis of the above LD voters seem less likely to contemplate voting tactically then LAB ones.