Labour has been accused of ‘gerrymandering’ after ministers allegedly overruled officials to redraw boundaries for new councils for ‘political reasons’.

The Government is facing legal action after new evidence suggested Steve Reed rejected advice from civil servants in favour of different council boundaries that critics say will benefit Labour.

The controversy centres around Labour’s plans for the biggest shake-up of local government in more than half a century, which would see dozens of councils replaced with new ‘unitary’ authorities.

A number of councils including Essex, Norfolk and Suffolk have all threatened to bring judicial reviews against the proposals, which could create significant delays to Labour’s plans.

Now evidence compiled by government lawyers has been shared with Essex county council - which covers more than 1.7 million people - in a pre-legal action letter.

It shows that officials recommended the creation of three new unitary councils in the area - but instead Local Government Secretary Steve Reed opted for five.

Civil servants warned Mr Reed that the five-council option would not be ‘financially viable within five years’ and ‘risked creating councils that are at significant disadvantage’.

But the Labour minister instead opted for five councils, arguing that his preferred boundaries would increase housebuilding around cities in the area.

Tory shadow local government secretary James Cleverly said it was ‘further proof that Labour’s election and local government changes are driven by party political considerations’.

The Essex MP added: ‘Not content with trying to deny democracy by cancelling local elections, Steve Reed is now resorting to gerrymandering the council system itself. It makes a mockery of Labour’s claims to be empowering local democracy.’

Sean Matthews, chair of the County Councils Network, said: ‘When officials are warning of serious financial and operational risks, ministers cannot simply ignore the evidence and hope for the best. Getting local government structures wrong can have consequences that last for decades.

‘These revelations now demand an urgent reassessment of the decisions already taken and the government must now fully disclose all the underpinning evidence and ministerial advice.’

The Government announced 15 new unitary councils will be created across Essex, Suffolk, Norfolk and Hampshire, with decisions to be confirmed on the number of unitary councils in 16 counties later this summer.

Suffolk and Norfolk county councils had proposed a single unitary authority in each area, while Essex and Hampshire opted for three.

But the Government instead decided on three unitary councils in Suffolk and Norfolk, four in Hampshire and five in Essex.

Essex, Suffolk, Hampshire, Norfolk, Thurrock and South Norfolk councils have all threatened to challenge Labour’s plans to redraw council boundaries in their areas in recent weeks.

A source pointed to better connections for local services for Mr Reed's reasoning for picking five councils in Essex. 

A spokesman for the Ministry of Housing, Communities and Local Government said: ‘We completely reject these allegations.

‘Decisions on local government reorganisation will be made transparently and in line with the published criteria - not on a party political basis.’