Roche, who has been a councillor for seven years and held the housing portfolio for two years, said resigning from the party was “really tough” as he had been a Labour supporter since the 1970s and his mum had been a trade unionist.
“It pulled at the heartstrings but we felt we had to do this to represent local democracy in Luton,” he added.
Roche said the council’s Labour Party members can force a no-confidence vote in a leader if 40% of them agree to the move, but added a review was instigated by Labour East in March on the political leadership of the authority.
He said: “The official outcome was never shared with the whole group and as such there was no opportunity to debate or respond to what their findings were.
“It was done via telephone interviews with a few selected people, MPs and councillors me included, and on completion Hazel Simmons was informed she must stand down but must do a statement resigning her post so effectively she was forced out.”