By Geoff Andrews, Local Government Correspondent

The main reason given by the Government for abandoning the rates system in favour of a poll tax is being challenged in a new analysis of the proposals,

It shows that instead of improving the accountability of councils to their electors the change seems likely to enable some councils to spend more and charge their electors less, while others will have to raise charges even if they economise. If the new system was already in operation in England a two adult household would on average be £23 a year, or 44p a week worse off according to this analysis.

The figures come from CIPFA, the independent Chartered Institute of Public Finance and Accountancy, which has applied the Government's proposals to the current budgets of all councils in England. It found that there is not one council in the country where changes in spending compared with last year would have been accurately reflected in a poll tax.

The figures also bring into dispute the Government's claim that the new tax will be much easier for voters to understand. Problems transferred into the new "simplified grant system" will obscure much of the advantage the poll tax, or community charge, is supposed to bring.

The study concludes that over the country there will be great differences in the way individuals and families are likely to be affected.

"It is difficult to envisage that without major changes of one kind or another most people in inner London will not pay more under a community charge than they do now, the study says. "Similarly, it seems likely that many people in outer London and the Home Counties would be better off in the long term.

In outer London the average would be £226, with a high of £365 (Waltham Forest) and a low of £158 (Bromley).

The average inner London charge would be £557.

In metropolitan districts the high would be £301 in Liverpool and the low £156 (Trafford). The average would be £231.

Shire districts would produce an average of £192 with Rochester upon Medway lowest at £131 and Brentwood highest at £339.

A safety net system cushioning people hardest hit by the change by transferring grant money from those who benefit will even out these differences considerably, at least in the first few years.

Paying for Local Government-- Update August 1987, £25 CIPFA Publications Department, 3 Robert Street, London WC2N 6BH