Liberal Democrat candidate Olly Glover criticised the behaviour of the Labour Party during the election campaign in Tooting.
Mr Glover received 8,305 votes, 14.2% of the overall vote and an 8.9 % increase on his party’s performance in the 2017 General Election.
Dr Rosena Allin-Khan received 30,811 votes to retain the seat which has been held by Labour since its creation in 1974.
Mr Glover said: “There was a lot of nonsense talked by some other parties, particularly Labour.
“They were a bit like the boy who cried wolf by saying the Tories being on the brink of winning in Tooting when that’s never happened so our vote was squeezed as part of that.
“I think their messaging was a little bit unnecessary.
“Nevertheless, I’m not disappointed at all. We nearly tripled our vote from last time so I’m really pleased.
“A lot of people on the campaign said they were tired of the same two political supermarkets and pleased to buy from a Liberal Democrat one.”
Despite the defeat, Mr Glover reflected optimistically on the campaign as a whole.
He added: “I felt it was a positive campaign. I enjoyed meeting the other candidates, the hustings were well-run, and I relished it.”
Dr Khan is a vocal remainer, which Mr Glover is relieved to see but he is determined to make sure she follows through on her promises.
He said: “I will definitely be keeping an eye on her as she was standing for the Labour Party not as an Independent.
“And many major members of the Labour Party such as Len McCluskey, Rebecca Long-Bailey and Jon Trickett have said that Labour is not a remain party or that they would want to back a Labour Brexit.
“Obviously, as we have seen tonight, Labour’s strategy of trying to be everything to everyone on Brexit has been unsuccessful.
“I will certainly be keeping an eye on her to make sure she holds true to her promises.”
Conservative candidate Kerry Briscoe came in second place with 16,504 votes but refused to speak to the media after the result.