Falmouth community activist Mathew McCarthy was elected as a Liberal Democrat member of Falmouth Town Council on Thursday in what is being described as a "decisive win" in the Penwerris ward of the town.

Mathew, whose campaign centred around parking problems, won with 353 votes. He said: "It will be an honour to serve local people in the Penwerris ward on the Falmouth Town Council. I knocked on almost every door in the ward twice during the election campaign and it was a real pleasure to meet so many lovely and warm people.

"It is clear that many people felt their voice had not been heard and I look forward to taking up many of the points raised on the doors as the local town councillor for Penwerris."

The election, which was the first contest in Cornwall since the general election, was seen as an important test for the Liberal Democrats. More than 16,500 have joined the party since May 7 in a self styled "fight back." The local Truro and Falmouth Association have seen their membership increase by a third.

Jeff Muir, chair of Falmouth and Penryn Liberal Democrats, said: "I am really delighted for Mathew. He worked so hard during the election campaign and it is a thoroughly deserved victory. I know Mathew is really thrilled to have received the trust of local people and I am sure that he will continue working hard for residents of Penwerris for many years to come."

By-election results: Mathew McCarthy, Liberal Democrat, 353 votes; Anna Gillett, Labour, 221 votes; Ann Congdon, Independent, 120 votes; Ayesha Wilson, Mebyon Kernow, 71 votes.

The by-election was held following the resignation of former deputy mayor, Gerald Chin-Quee, who stood down after 16 years because of work commitments.