Ms Taylor confirmed Mr Towill emailed her on Monday to say he would stand as a Reform UK candidate on May 1 and had switched parties.
She said it was a big disappointment but that Mr Towill would remain a good friend.
Ms Taylor said: “It is very sad that Kevin has made this decision as he’s been a real stalwart for us.
“I will continue to treat him as a good friend and he still has a lot of friends in the party.”
Hundreds of people attended the event, at which former Conservative minister Ann Widdecombe, now a member of Reform UK, gave a speech.
However, a large group gathered outside the leisure centre to protest against the rally.
Her speech will be delivered a day after a series of international events to mark the third anniversary of Russia's invasion of Ukraine.Discussions around peace
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