The deputy leader of the Liberal Democrats has accused Zac Goldsmith of "dog-whistling, racist, personal attacks" during his bid to become London mayor.
Jo Swinson condemned Tory Mr Goldsmith's controversial campaign tactics against Sadiq Khan, calling them "unacceptable".
Addressing a rally at the Lib Dem conference, Ms Swinson compared the Lib Dems to Chumbawamba, as the party that got knocked down but got back up again.
The event rounded off the first day of activities in the main hall at the party's conference in Bournemouth.
Ms Swinson praised the party's clarity on the EU, as well as the Lib Dem by-election win over Mr Goldsmith in Richmond Park last December.
"That victory had deeper resonance too, because it showed how people from different party backgrounds could come together to send a message about the kind of politics we want.
"Or more accurately, what we do not want.
"The kind of dog-whistling, racist, personal attack campaign that Zac Goldsmith endorsed in his mayoral bid against Sadiq Khan is unacceptable and should have no place in our democracy."
Mr Goldsmith won the seat back from the Lib Dems at the snap General Election.