Following the latest council election Hertsmere's Labour Group has lost its role as the borough's official opposition.
Borehamwood's Labour Group now has the same number of seats as the Liberal Democrat Group, so neither party is automatically recognised as the opposition.
Even if Labour joined forces with the Liberals, the two groups would have nowhere near enough votes to beat the ruling Conservatives, who have 25 seats while Labour and the Liberals have seven each.
At its annual general meeting on Monday, the Labour Group voted in Councillor Leon Reefe as leader, replacing Councillor Len Silverstone, who only took over as group leader from Councillor Frank Ward a year ago.
In a press statement the Labour Group said Mr Silverstone had stood down from the leadership because of work and personal commitments.
"Councillor Reefe, in thanking his colleagues for their support, made it clear that his objective during his term of office will be to see the Labour Party in Hertsmere regain the ground that has been lost over the last five years," said the statement.
Mr Reefe said: "My aim is to return the Labour Party to power in Hertsmere as soon as possible so that we can once again provide the services for people that they really need." He praised Mr Silverstone's work during his time as leader.
Councillor Michael Colne, leader of the Liberal Democrats, said: "I think the significant difference is that there ceases to be a leader of the opposition. I think we will have to run along without an official opposition for a while.
"But this is a gain for Hertsmere, as it gives us more influence," he said.
Mr Colne, who has been with the council since it was established in 1977, conceded that Borehamwood's Labour politicians would lose some of their clout now that they were no longer in the second biggest group on the council, but added that the loss of Labour seats in Borehamwood reflected the changes taking place in the town, from being an overspill London neighbourhood to a more diverse community.