The problem with eliminating the Tory party is that something worse may appear in its place.
Eradicating a party doesn't get rid of all of its voters, there will still be a significant number of right-of-centre people in the country and many of them vote.
The danger is that without a just-right-of-centre party to vote for they end up voting for something further right.
Labour's danger is that moving too far left will mean that people who can't stomach voting that far left stop voting Labour or, even worse (for Labour), vote for a party right-of-centre.
Thankfully, and as previously cited somewhere in this thread, the Tories are losing members/voters to death from old age at the rate of 25k per day, which aren't being replaced by those who would choose to vote Tory.
The problem with eliminating the Tory party is that something worse may appear in its place.
Eradicating a party doesn't get rid of all of its voters, there will still be a significant number of right-of-centre people in the country and many of them vote.
The danger is that without a just-right-of-centre party to vote for they end up voting for something further right.
Labour's danger is that moving too far left will mean that people who can't stomach voting that far left stop voting Labour or, even worse (for Labour), vote for a party right-of-centre.