The betdata.io chart of the Betfair market tells its own story. After the vacancy in the seat was triggered punters made LAB and the Tories almost level pegging. Now that edged has out and in the latest version of the chart the Tories are 11% behind in the betting.
There was a poll from Focaldata that had LAB ahead.
One thing that might make this harder to call is that the pandemic means no doorstep canvassing reports of which in the past have proved to be a good guide in contests like this.
This is the Wikipedia chart of how votes have changed in the seat since 1974.