A £22m project that will see major engineering works on ponds across Hampstead Heath was given the green light tonight (Thursday) by the Town Hall.

Heath managers the City of London had applied for permission to radically alter a series of ponds across the open space – after being warned by engineers that increasingly severe weather patterns means dams holding back millions of gallons of water were at risk of collapsing and causing a disastrous flood downstream.

The scheme – first mooted in 2011 – has caused huge controversy.

The Town Hall's development control committee heard the work would increase flood storage capacity, reinforce and raise the height of pond banks, build 'spill ways' for water to flow downstream, and includes landscaping. The project includes increasing the size of the Highgate boating pond and scooping out a new, 100 metre long, 18-foot deep, and 40 metres wide 'catchpit' in dense undergrowth near the Vale of Health to hold water back if a severe storm hit London.

The 10-strong committee voted six in favour and three against, with one abstention.

Speaking after the meeting, Heath superintendent Bob Warnock said the City would take their obligations to protect the land during the works seriously. He said: “This confirms our process of putting the landscape at the heart of this scheme.”

He added that once the work had been completed, the Heath would be in better shape.

Mr Warnock said: “Nature has a fantastic ability to recover and we will return the landscape back to the Heath we all know, love and cherish.”

The City estimate work will run until October 2016, and will need thousands of trips by heavy lorries, diggers and cranes to complete.

The work, the City of London's application argued, was needed to meet the demands of the Flood and Water Management Act of 2010. The Act reviewed the risk of reservoirs suffering a collapse of their banks – and with Hampstead Heath situated in a heavily built up area, it was seen as a posing a serious risk to life if any banks were breached.

>> SEE HOW THE NEW JOURNAL LIVE-BLOGGED THE PLANNING MEETING THAT CHANGED THE HEATH <<

The controversial application prompted nearly thousands objections to be lodged, and a petition with more than 10,000 signatories had also been delivered.

Heath and Hampstead Society chairman Marc Hutchinson called the application the “…most important regarding an open space the council has ever had to consider.”

He added: “It poses the biggest threat since the 1890s, when the London County Council tried to turn the Heath into a park.” He countered claims that the City were legally obligated to do the work, and added: “The officers report agrees that some features are 'inappropriate development.' We object, for example, to the building of a catch pit. It will be 18 foot high – it beggars belief the report claims it will have no effect on the Heath.”

After hearing the result, Mr Hutchinson said the Society would now appeal directly to the Secretary of State for the Environment Elizabeth Truss and ask her to exempt the Heath from the legislation.

He said: “That is the last course of action open to us.”

Swimmers deputations were lead by Jane Shallice of the Kenwood Ladies Pond Association and Geoffrey Goss of the Highgate Men's Pond Association. Both swimming associations spoke against the plans. The meeting heard the Men's Pond would be closed through November and part of December, the Mixed Ponds shut in January of 2016, and the Ladies Pond closed between February and May. The application includes allowing for women's only sessions at the Men's and Mixed ponds while the Ladies Pond is closed, and longer opening hours at the Parliament Hill Lido.

Robert Mann, of engineering firm Aecom who reviewed the application for the Town Hall, insisted calls by objectors for a flood warning system and evacuation plan instead was 'unrealistic.'

He said: “The Heath has a large number of dams to keep an eye on. You'd have to have people running from one dam to another, peering through trees.”

His firms report concluded that “the proposed works are necessary and proportionate…the need to mitigate the risks of potential loss of life from dam failure are considered to clearly outweigh any harm to the Metropolitan Open Land.”

Work is due to start in February.

HOW THEY VOTED

For:

Cllrs Freeman, Olewski, Leyland, Beales, Harrison, Jones

Against:

Cllrs Vincent, Headlam-Wells, Rea

Abstained:

Cllr Stark

'A CURE FOR NO KNOWN DISEASE', COUNCIL TOLD

THE passion people feel for Hampstead Heath was reflected in the fact all deputations – whether for or against – claimed to have the interests of the Heath at the centre of their arguments.

Heath walker Linda Cook, who highlighted the loss of trees that provided a habitat for ducks, queried whether the work went against the City's own biodiversity plans for the area, while fellow Heath user Brian Simpson called the work a “massive reconfiguration…that will be permanently disfiguring.”

He added: “This dam scheme is a cure for which there is no known disease.”

Others reminded the meeting it was a landscape that 19th century painter John Constable would still recognise.

Highgate ward Green councillor Sian Berry asked why 'softer' engineering options hadn't been fully explored, suggesting ideas had been sent in by independent experts but had not been taken into account.

Sir Christopher Kelly, the civil servant who chaired the Whitehall investigation into the expenses scandal, spoke in favour of the application on behalf of people living in Brookfield Mansions, Highgate West Hill. He said: “We care for the Heath. That is why we live where we do.

“Our homes are directly beneath the ponds chain. It is our homes – and our lives – that are at risk.”

Charles Leonard, of the Elaine Grove and Oak Village Residents Association, said that the argument the dams had not failed yet did not mean it would not happen in the future. He said: “We live in genuine fear. The risk is substantial. It would be extraordinary for the committee not to believe these experts and professionals.”

Gospel Oak Labour councillor Maeve McCormack said the risk of flooding 'seriously concerned' her constituents. Her fellow Labour councillor Sally Gimson spoke of “…families racing to get out of the way of a coming Tsunami” and highlighted four schools that could be threatened by a flood.