The centre of Carlisle could be transformed into an oasis of greenery boasting rooftop gardens, vegetation-covered walls and mossy monoliths.

The ideas have been mooted by leading city councillors in a bid to make the city more attractive for visitors, to soak up air pollution and to offset carbon emissions.

The early stage proposals come as the city council prepares to launch a public consultation on its eco-strategy.

The move comes almost a year after Carlisle City Council declared a climate emergency, pledging to become carbon neutral by 2030 – though some campaigners want to bring this forward to 2025.

The executive hopes that the proposed “greening” of the urban realm will not only have ecological but economic benefits.

They believe that the creation of a pleasant garden city, with buildings covered where possible in carpets of moss and grass, will encourage more people to spend time and money in the city centre, boosting trade.

Councillor Nigel Christian, who holds the Environment and Transport Portfolio, said similar projects had been rolled out successfully in other cities across the UK.

“It could be a fabulous thing to do and would be part of a whole package of measures to tackle climate change,” he added.

He stressed that the district authority was “very interested” to hear additional suggestions from the public, including how they think the improvements to the Carlisle Station Gateway should develop.

The council is also considering offering financial support to community groups as part of a tree-planting programme on the rural outskirts and wants to improve cycling routes into Carlisle.

Among the other ideas being considered is installing so-called ‘CityTrees’, towering structures covered in moss that have the pollution-cleaning power of a small forest.

Some of these eco-friendly monoliths have already been installed in some of London’s pollution hotspots to tackle the city’s filthy air.

Dubbed the ‘world’s first biotech pollution filter’, the CityTrees use living plants to filter pollution from the air locally to benefit residents and passers-by. The devices — each of which has the pollution-reduction benefits of 275 trees — are the product of Waltham Forest’s collaboration with clean tech firm Evergen.

The state-of-the-art technology uses living plants and different types of mosses to capture toxins and remove pollutants from the environment to produce clean air.