Last night the Council co-pted a new member to fill a vacancy as no election had been called. Those who put themselves forward were: a man whose political allegiance was not declared or known (at least to me), a current Conservative Party borough councillor and a former borough councillor who described himself as supporting the Labour Party.
The vote, which was in the public session and by a show of hands, was seven for each of the last two candidates. The former borough councillor (Labour) was then duly elected on the casting vote of the chairman.
Six out of the seven council members who voted for him, including the chairman, were 'elected' unopposed as Labour members in 2011. That is, there was no actual ballot and none needed any votes.
I understand that the above procedure was entirely lawful.