An ex-council semi given a 'ghastly' modern makeover has been ruthlessly mocked online after it was listed for £850,000.

The red-brick 1950s home appears completely unremarkable from the front - but has been blown apart at the rear by a towering double-storey extension so jarring that online wags says it looks like 'a UFO crashed into a suburban terrace'.

The garish pad, in St Albans, Herts, erupts at the back into a white-rendered wedge, complete with floor to ceiling 'cathedral' windows, timber cladding and artificial grass.

The home bought for £296,000 in 2012 is being hailed by its owners Sujal and Tina Patel in a sales brochure as 'a modern, energy-efficient home that combines technology with comfort'.

However, as photos of the four-bed house circulated online, critics were quick to pour scorn on the design.

One social media user branded the angular 5.2m-long extension as the 'Toblerone from hell', as another dryly joked how the rebuild was 'perfectly in-keeping with the street aesthetic'.

Others were less subtle, branding it as 'dreadful', 'sterile' and 'ghastly' and asking pointedly: 'Did they run out of money before rendering the front?'

Another simply concluded: 'Council out the front, Grand Designs at the back.' While one X user commented: 'These kind of pointless upgrades are keeping our nation’s tradesmen in work.'

The red-brick 1950s home appears completely unremarkable from the front. The ex-council semi is pictured here

But it has been blown apart at the rear by a towering double-storey extension so jarring that online wags says it looks like 'a UFO crashed into a suburban terrace'

Sympathy quickly turned to the neighbours in Nelson Avenue, too.

One onlooker wondered: 'Surprised the house [next door] hasn't thrown a brick into their extension given the loss of light.'

Another aimed their fire at the planning system itself, writing: 'UK planning regs are so insane.

'You can’t build anything new, but you CAN do the ugliest, most oversized, out of character extension to your ugly post war Lego box house.'

The head-scratching extension was nonetheless given planning permission in 2019, despite objections from neighbours warning it would dominate their home.

Planning papers reveal how the Patels' neighbours Lehna and Matthew Gardiner complained the structure’s 'extreme height and depth' would 'dominate the outlook from our living room, kitchen, back bedroom and garden' and leave them feeling 'hemmed in'.

They added: 'The proposed large gable end windows on the first floor will overlook our garden and remove the sense of privacy which we currently enjoy.

'The size of the proposed extension is out of keeping with the scale of the existing dwelling and the neighbouring properties on either side. This is aggravated by the imposing nature of the design, specifically its footprint extending 5 metres into the garden.'