This has been a bittersweet week for Phelim Mac Cafferty, the new convenor of the Green Party in Brighton and Hove.

He has at last assumed the mantle he has long cherished, but he has done so at a time when, on the face of it, he is least able to pursue the vision he holds for the future of the city.

Last weekend, Mac Cafferty saw his beloved party reduced to a rump in the council chamber, while his long time nemesis, Warren Morgan, leader of the Labour Group, watched his party assume minority control.

To say that Morgan and Mac Cafferty don’t get along is like declaring that Itchy and Scratchy never entirely saw eye to eye.

Mac Cafferty is a fierce champion of the marginalised and disadvantaged communities and he will have little sympathy with the New Labour cast of the new administration. He will want to speak up for those whose voice is rarely heard amid the self-congratulatory noise of more powerful groups.

As hard as it may be, tribal loyalties must be set aside.

The Labour Group, for their part, must not indulge in any form of triumphalism. Its victory seems impressive in stark seat numbers, but it could be overturned in an instant. Council work is unglamorous and largely thankless.

The new administration faces a daunting challenge – it must protect vital services while its resources are cut to the bone.

The job for the Green Party under Phelim Mac Cafferty is to hold Labour to account but to support the administration in its efforts to make the city a safer, cleaner, and, yes, Greener, place to live.

John Keenan is a journalist