A referendum on the creation of one ‘mega-council’ in Lincolnshire would cost in excess of £1m despite previous county council assurances costs would be ‘kept to a minimum’.

Lincolnshire County Council had planned to hold a poll on proposals to abolish the county’s eight councils and replace them with a unitary authority.

The poll was to be held at the same time as the May local government elections, a move the county leader Martin Hill said would keep costs to a minimum.

However, Ric Metcalfe, leader of City of Lincoln Council and an opponent of the unitary plans said the referendum would cost Lincolnshire tax payers an estimated £1m.

Citing legal advice received by all the district councils from Timothy Straker QC, Cllr Metcalfe insisted any attempt by the county council to combine their elections with a referendum on local government transformation would be ‘unlawful’.

‘The county council has stated on several occasions that it intends to run a referendum on 4 May to gauge support for a unitary authority,’ he said.

‘This is the same date as their elections and there are significant legal obstacles about holding a referendum on this day.

‘At this stage, this means the only way a referendum could take place would be to hold it completely separately or on another date, incurring a cost to the Lincolnshire taxpayer more than £1m.

‘I do not believe that anyone would view this as a good use of taxpayers’ money, especially as the outcome would not be binding.’

‘If the county council had consulted on this proposal with any of the district councils prior to their announcement, we could have raised our concerns then. Sadly, they did not,’ he added.

‘I and my district colleagues are in favour of a collective debate on the future of local government in Lincolnshire, but to hold a referendum at such an early stage in discussions is ludicrous, especially at such massive cost.’

Responding to the city council’s criticisms, the county council leader Martin Hill said that he did not ‘personally agree with their legal and other objections’ but would postpone the planned referendum.

He said that while it was ‘deeply disappointing’, he could not require the district councils to help with holding a poll.

The councillor reiterated his continued support for the overhaul of the county’s local government structures – a reform he has previously noted that would save £150m.

However, there is opposition from the county’s district councils.

‘A remote unitary mega council for the whole of Lincolnshire would be ridiculous – we are one of the largest counties in the UK and contain a diverse range of areas with significantly differing challenges and needs,’ said Cllr Metcalfe.

‘A county unitary would be too remote a tier of government - district councils are best placed to deliver services that meet the needs of all their residents and businesses and we want to protect these services.

‘This will not happen under a county unitary.’