The Liberal Democrats are talking a lot about the blue wall.
These are traditional Conservative seats where they hope Tory voters have had enough of the present government, can’t bring themselves to vote Labour - and see the Lib Dems as an acceptable alternative.
Bold of you to assume voters care about consistency or policies. For many Tory upporters in the Home Counties, southeast, southwest and east London, voting Labour would be a bridge too far. But the Lib Dems might be an acceptable alternative. There’s a reason the main left of centre party in these regions is the Lib Dems, and not Labour.