On Thursday 7 September 2017, voters took to the polls to vote in the East Cambridgeshire District Council Ely South Ward By-Election.

The count venue was the Council Chamber at East Cambridgeshire District Council, The Grange, Nutholt Lane, Ely.

The turnout was announced as 40.2%.

At 23:15pm, the Returning Officer, John Hill, declared the count totals, which are as follows: 
The total number of ballot papers counted was 1325
The number of votes cast in favour of Sarah Louise Bellow (The Conservative Party) – 411
The number of votes cast in favour of Rebecca Anne Denness (Labour Party) – 384
The number of votes cast in favour of Christine Whelan (Liberal Democrats) - 527
 

The total number of rejected ballot papers was 3.
The winning candidate is confirmed as Christine Whelan.