Christine Simpson was the first Labour councillor in Brighton to be beaten by the Greens back in the mid 1990s.

Labour was riding high at the time and to some socialists the win by Pete West seemed like a minor aberration.

But council leader Steve Bassam was alarmed and his fears proved correct. The Greens made remorseless progress, initially at Labour’s expense.

Their numbers at least doubled at every election as they took city centre seats and the process continued when the new combined council with Hove was formed.

As Tories took over and Labour relapsed into opposition, the Greens had almost as many councillors. Then they drew level at a by-election in Goldsmid ward and also claimed their first seat in Hove.

Now anyone attending the annual meeting of the council tomorrow will see they are the largest party with 23 of the 54 seats and their advance has been bad news for all the other parties.

Lone Liberal Democrat Paul Elgood was defeated after hanging on against the odds for 12 years. Labour failed to make any progress, their gains from Tories being wiped out by losses to the Greens.

These included Christine Simpson. Having returned to the council in the apparently safe seat of Hollingdean and Stanmer, she lost, along with the long-serving Pat Hawkes.

As for the Tories, they lost some of their most able councillors such as Ayas Fallon-Khan to Labour, More ominously, they gave way to the Greens in strongholds.

It was astonishing that writer Christopher Hawtree should get elected in Central Hove and even more remarkable that Tories should shed a seat in leafy Withdean.

All the time the Greens were stuck in the city centre they were doomed to be a party of opposition.

Now they can reach into the suburbs, they have the capacity to take control of the council in 2015.

They may never do it. Greens are the largest party and will form a minority administration but they will need the help of opposition votes to get things through.

Both Labour and the Tories have headed minority groups in the past eight years. It can be done but it is difficult.

Greens may also find in Brighton and Hove, as Lib Dems did nationally last year, that brickbats fly once a party governs.

It’s easy to shout from the sidelines but quite another matter to take unpopular decisions when in power.

There are some wise heads in the Green group. Convenor Bill Randall is sound. Ian Davey is intelligent and able.

But there are also some mavericks and many of the new councillors, some already in high office, are unknown quantities.

Greens pride themselves on their individuality but must be disciplined to achieve success.

In the 1970s, Liberals gained control of Eastbourne Council and were not prepared for it. The electorate soon voted them out again and the town rever ted to the Tories.

Early indications from the Greens have been promising.

They have made some sensible proposals on transport. Naturally they want to make environmental improvements.

But they have to work within a budget largely suggested by the Tories in February in a climate of enormous public service cuts.

Greens may also find substantial opposition to some of their policies such as giving more help to travellers because many people are having bad experiences with them.

Top officials may not relish the prospect of working with a minority untested administration – especially as Greens opposed some of their appointments.

But co-operation between councillors and officers is essential for the city.

It won’t have escaped the attention of the old parties that hard work and personality paid dividends in these elections. For Labour, Brian Fitch was able to bounce back in Hangleton and Jeane Lepper survived in Hollingdean because they put in the time and were well known.

In North and South Portslade, Bob Carden and Les Hamilton were far ahead of any other candidates for the same reason.

The Green success was also a Brighton phenomenon rather than a British one and the party came far short of making a national breakthrough.

My brother Jolyon, standing as a Green in Kent, found his vote slumping from 22% two years ago to 5% this time and he was not alone in that.

So unless they are skilful, determined and lucky, Greens could find they have peaked now.

And Christine Simpson might also be the last Labour councillor in Brighton to lose to them.