Richer householders could face massive bills under radical Green plans to shake up the council tax system in Brighton and Hove.

In a move never seen before in the country, party activists have agreed to explore the possibility of Brighton and Hove City Council revamping its system of local rates.

The “progressive council tax” would see a “steep increase” in the amount billed to each of the city’s 120,000 households.

However, advocates claim only the richest 20% would end up paying the hike as four-fifths of homes would be eligible for a discount.

Some Greens believe it would be a fairer way of raising revenue as the Government cuts town hall budgets by millions of pounds every year.

However, critics slammed it as “dangerous” and “unworkable”, adding it could see the richest pay up to 200% more in council tax every year.

Council leader Jason Kitcat said: “It’s really refreshing to see party members coming up with ideas which seek to minimise the draconian cuts being handed down by this coalition Government which have been adding further to the problems heaped on our city by Westminster.

“No other party in the city seems even interested in tackling austerity.”

Currently the Government has placed a cap of 2% on any annual increase in council tax.

Any rise above that can only be introduced after an area-wide referendum.

If they agree to push ahead with the idea, “progressive council tax” would see the council’s Green administration propose a steep rise in the rates and then hold a city-wide vote.

If approved, 80% of city residents would be eligible for a reduction which would be “means-tested”, based on residents’ income and ability to pay.

Advocates claim a majority of households would end up paying less than they currently do.

According to a Green member, “the higher the increase, the less the majority will pay”.

Exact details and costs of the scheme are now being looked at by Green members.

But a briefing sheet produced for Labour Party members which has been seen by The Argus claimed increases of 200% would be needed to pay for administration costs and ensure enough money was raised to limit the impact of Government cuts.

If this figure was applied, it means those in band H – the highest council tax category – would see their annual rates increase from £3,014.56 to £9,043.68.

Labour councillor Gill Mitchell said: “This sounds like another crackpot scheme being dreamt up by the Greens where they decide who is worthy of a council tax reduction and they decide who should pay more.

“It sounds dangerous and we would be against it.”

Conservative councillor Ann Nor- man said: “I just cannot see how it would work.”

She added: “I think we need to keep at the lowest level of council tax we can.

“As a party we normally try and go for a freeze unless there is some near catastrophe.”

A Green Party spokesman said the idea was one of “many avenues” members in the Brighton and Hove were exploring to “minimise the effects of Government cuts on the city’s residents”.

He added council officers would not spend any time helping to draw up the plans although they may be asked for information already in the public domain to help develop the idea.

The spokesman said a decision on whether it is taken forward will be taken in the coming months.