Weymouth and Portland Borough Council was a hung council before the local elections. This means that no one party was in overall control – although the Conservatives were the largest group.

The situation did not change after the elections, although the size of the groups has altered.

After the election and Councillor Petherick’s switch, the new council will have three independent councillors, seven Labour councillors, 10 Liberal Democrats and 16 Conservatives.

Mayor of Weymouth and Portland Borough Council Paul Kimber said the decision would mean an ‘exciting time’ for the future of politics in the borough.

He said: “I’m quite surprised, almost shocked to see what’s happened. I can only imagine there must have been quite an argument in their group as to the direction they wished to travel. Obviously now the council is very much hung, more hung than ever.

“It makes for exciting politics in Weymouth and Portland.”

Liberal Democrat group leader Ian Roebuck was surprised by the news.

He said: “To be quite frank I’m surprised that the party decided to change leader. I thought Geoff did a good job over the last year.”