The case of Sherlock's home: Benedict Cumberbatch faces a planning battle with neighbours who object to him building a boiler room in his new £3m London townhouse 

Sherlock star Benedict Cumberbatch faces a lengthy planning battle with neighbours after concerns were raised over his plans to build a 'noisy' boiler room at his new £3million London townhouse.

The 39-year-old snapped up a five-bedroom mansion in Camden, north London, for just over £2.7million last April - but baffled neighbours by not moving into the home.

Instead, the actor - who married opera director Sophie Hunter last year - got builders to put up huge black hoardings around the Victorian property while he made plans to renovate and extend it.

He submitted plans to Camden Council to add another bedroom via an attic conversion - and also install a 'plant room', with a water heater and boiler in it, at the front of his semi-detached house.

Sherlock star Benedict Cumberbatch is facing a lengthy planning battle with neighbours after concerns were raised over his plans to build a 'noisy' boiler room at his new £3million mansion in Camden, north London (centre), which he bought last year but still hasn't moved in to

The 39-year-old snapped up a five-bedroom mansion in Camden, north London, for just over £2.7million last April - but baffled neighbours by not moving into the home. Instead, he had builders erect black hoardings outside it while he submitted plans to extend the property

The actor - who married opera director Sophie Hunter last year (pictured together at a red carpet event last October) - got builders to put up huge black hoardings around the Victorian property while he made plans to renovate the new home and extend it to include more rooms

The Harrow-educated actor, who stars in The Jungle book and The Hobbit, also wants to build a rear extension to the property, but has promised not to chop down an established magnolia tree.

A sticking point, raised by Camden Council - and neighbours - is the plant/boiler room, which according to plans would be 'installed in the front garden beneath the existing retaining wall'.

The plans state: 'It is proposed a plant room be installed in the front garden beneath the existing retaining wall.'

It adds: '[The road] is a wide, tree-lined avenue with substantial detached, semi-detached and short terraces of mid to late Victorian and Edwardian villas.

'There is an established residential land use pattern across the area.'

The council report, however, claims that planning officials may need to call for an 'acoustic report' to find out if there are any 'noise issues' related to the plant room in the front garden.

The report says: 'An acoustic report would be required to accompany the application to check there would be no noise issues in relation to the plant room in the front garden.'

The council report states that the alterations are 'generally acceptable', concluding: 'The proposed rear extension and access stair are considered generally acceptable, as are the fenestration changes.

'The front rooflight should be reduced in size and the rear dormer should be revised to be a more traditional style.

'An acoustic report will need to accompany the plant room and proposed landscaping of the front garden should be provided in a plan.'

The Harrow-educated actor, who stars in The Jungle book and The Hobbit, also wants to build a rear extension to the property, but has promised not to chop down an established magnolia tree. He also wants to add an attic conversion to make more rooms (one is pictured)

Camden Council - and neighbours - have raised concerns about the proposed plant/boiler room, which according to plans would be 'installed in the front garden beneath the existing retaining wall'. They claim it could be 'noisy' and have suggested tests be carried out

The actor's architects, Charles Tashima, said in planning documents that the plans 'would respect and preserve the original design and proportions of the building, including its architectural period and style'. Pictured: One of the sitting rooms in the £3m London townhouse

In a letter from Ian Wallbank, the head of acoustic services at building consultants Stroma Tech dated April 20 2016, he says the so-called plant room is due to be fitted with a 'hot water boiler'.

He said that normally it would not cause a 'noise issue' and he is currently awaiting the council's decision on whether to carry out a night-time noise assessment.

His letter to Camden Council states: 'We would need to visit site and undertake a background noise assessment at the nearest noise sensitive receiver over the night time period and undertake calculations to determine compliance with relevant guidelines.'

He adds: 'This would be an onerous requirement to assess the noise impact from a domestic boiler and I would ask the planning Authority (Camden Council) to clarify their expectations on noise limits should it be confirmed a noise impact assessment is required.'

One neighbour, who asked not to be named, said locals were 'annoyed' when the actor didn't move straight in last April - saying the three-storey house is in 'perfect order'.

She told the Camden New Journal: 'There was a little frisson of excitement that he (Cumberbatch) was moving into the neighbourhood.

'We were hoping he may come and present some prizes at our street party.

'But the excitement quickly turned to boredom and then displeasure after his builders put up ugly black hoardings around what is a rather pretty home and then left it empty for ages.'

One neighbour said locals were 'annoyed' when the actor didn't move straight in last April - saying the mansion is in 'perfect order'

The actor bought the house after the death of solicitor Judy Walker, who died last year and was renowned for holding Bonfire Night parties

The planning documents state that none of the changes could be seen from public spaces or 'adversely affect the conservation area'

The actor has submitted planning documents in which he outlines plans for a boiler/plant room in the front garden (shown right, above)

Planning documents show the make up of the property which includes five bedrooms, a reception area, living room and large garden

Another neighbour, who again asked not to be identified, said: 'I see he's getting his attic converted and wants a rear extension to the basement, but the thing that's got people worried is this boiler room at the front of the house.

'We don't know if it's going to be this big noisy boiler room or not - and the council and architects can't seem to make their minds up as to whether it will be a problem or not.'

The actor's architects, Charles Tashima, said in planning documents that the plans 'would respect and preserve the original design and proportions of the building, including its architectural period and style'.

It states that none of the changes could be seen from public spaces or 'adversely affect the conservation area.

The actor bought the house after the death of solicitor Judy Walker, who died last year and was renowned for holding an annual Bonfire Night party.

She was married to the late Labour councillor at Camden Council Ivor Walker, who died in 2009.

A spokesman for Camden Council said the decision would normally be made by planning officers, but that if more than three neighbours object to the plans it will go to the council's planning committee.

The council is set to make a decision on whether to send in the noise inspectors in the coming weeks, with planning permission on hold until a decision is made.