Families looking to make major extensions and home improvements face a doubling of planning application fees following a Budget tax grab.

The housing secretary and deputy prime minister, Angela Rayner, has outlined plans to make it easier for people to extend their properties by removing planning controls.

However, at the same time people making an application to their local council to carry out a major change will see the fee rise from £258 to £528 “at the earliest opportunity” in order to boost council income.

It is hoped the cash will be used to hire and retain more planning staff and so speed up decisions on planning which have held up attempts to build more homes.

Separately, councils across the country are also looking to impose an inflation busting 5 percent increase in Council Tax from April despite an increase in funding from the government.

Government documents have admitted there is a concern that the increase in fees might lead some people to push ahead with building projects without getting permission.

Papers released by the Ministry of Housing, Communities & Local Government admit its “significant” price surge could lead to an increase in homeowners skipping legalities.

In papers published online, it stated: “We recognise that an unintended consequence of an increased fee may be increased unauthorised development. Local planning authorities have responsibility for taking whatever enforcement action may be necessary.”

Currently, the existing charge of £258 does not cover the costs incurred by local authorities to process applications, meaning they effectively make a loss. A set fee of £528, however, will mean they can break even.

But Chris May, of law firm Freeths, told the Telegraph that the cost calculation is “arbitrary”, while property consultant John Howard stressed that the doubling of fees “will surely lead to more illegal activity”.

Mr Howard said: “It seems a very odd route to take when you try to encourage homeowners to increase the housing stock available.

“It’s another extra cost for people looking to bring vacant properties back into use – something that is hugely important if we’re going to improve the housing situation for many people in the UK.”

Joseph Lane, of brokerage Mortgage Lane, said: “This steep rise in fees could deter homeowners from securing the necessary permissions, paradoxically at a time when the Government aims to encourage the conversion of empty properties into homes.”

The increased application fee was suggested by the Government in its consultation on the proposed overhaul to the National Planning Policy Framework (NPPF).

Survey responses highlighted how the £528 fee would become “an extra burden for minor works on listed buildings and in conservation areas”.

Concerns were raised that a rise in the number of unauthorised developments would pile further pressure on council enforcement services.

The majority of British homeowners bidding to extend their property will not be affected by the rise in fees as, rather than having to apply for planning permission, work is covered by permitted development rights.

However, homeowners seeking larger-scale build-outs will be affected by the inflated cost. Meanwhile, planning application fees for smaller property changes, such as the construction of gates or fences will remain at £258.

Stuart Tym, of law firm Knights, has called for all money raised from application fees to go into the planning system.

He said: “Unless the Government ring-fences any planning fees, price changes are pointless.

“Without ring-fencing, the monies will go into the council’s general budget and will unlikely be of any benefit to the planning service at all.”

Alistair Watson, of law firm Taylor Wessin, said: “The planning system has been starved of cash and a well-resourced system is vital to the social, economic and environmental health of the nation.”

A government spokesman said: “We cannot achieve our ambition to deliver 1.5 million homes and sustained economic growth without well resourced, efficient planning services.

“Councils currently have to subsidise their planning service from wider council budgets, as the fee charged does not meet the cost of processing each application. The increase will put planning departments on a sustainable financial footing to be able to provide a better service.”