A constituency opinion poll in the constituency where Heidi Allen was MP suggests the Liberal Democrats are running neck and neck with the Conservatives.
Heidi Allen was elected as a Conservative but after leaving the party to lead Change UK has since defected to the Liberal Democrats but decided to stand down at this election.
A survey conducted by pollsters Survation on behalf of the Liberal Democrats suggests the party is in the lead ahead of the Tories in the South Cambridgeshire constituency.
Although with a margin of error of plus or minus 5%, the result is too close to call.
The poll puts the Liberal Democrats on 40%, the Conservatives on 36% and Labour on 12%.
At the last election in 2017, Heidi Allen won the seat for the Tories with 52% of the vote and a comfortable majority of 15,952.
The Liberal Democrats were in third place with 12,102 votes and a 19% share which was well behind Labour.
The telephone poll of 410 people was conducted by Survation on 4 and 5 November.
Like Cambridge, South Cambridgeshire was one of only a few constituencies in the Anglia region which voted to remain in the EU referendum.
The Liberal Democrats made sweeping gains on the local council in 2018 taking an overall majority for the first time in the council's history.
Survation have been conducting other constituency polls in Cambridgeshire on behalf of the Liberal Democrats.
In the Conservative-held seat of South East Cambridgeshire, a poll of 408 people on 25-28 October put the Conservatives on 42%, ahead of the Liberal Democrats on 31% and Labour on 16%.
In the Labour-held seat of Cambridge, a poll of 417 people on 16-17 October put the Lib Dems ahead of Labour on 39% and 30% respectively with the Conservatives behind the Greens on 10% and 12% respectively.
Constituency opinion polls have a margin of error of plus or minus 5% which means the South Cambridgeshire survey could have the Conservatives on 41% and the Liberal Democrats on 35%.