A new island could be created in the Model Boating Pond on Hampstead Heath as part of proposed dam works to protect against life-threatening floods.

This is one of the most dramatic landscape changes that can be seen in the first images released by Atkins, the engineering firm designing the controversial £15million project for the City of London Corporation, which runs the Heath.

The new pictures, issued on Tuesday, show how the Heath would look if the dam between the boating pond and the men’s bathing pond were raised by three metres.

An island or peninsula is created with water now on either side of a cluster of large trees.

Tony Ghilchik, chairman of the Heath sub-committee on the Heath and Hampstead Society, said members of a stakeholders’ group who have been shown the designs were left deeply divided.

He said: “Some people thought it was not too bad, some people thought ‘my god it’s far too much’.

“Whatever is done, some people won’t like it and if nothing is done, people living south of the Heath won’t like that either.

“The corporation has got to make it safe – no question about that.”

The City claims lives could be lost in areas like Gospel Oak in the event of a catastrophic storm if it does not act.

The latest Atkins report, which includes the new images, outlines a new shortlist of ways to stop that happening.

There are four alternatives for the Highgate pond chain, which would see the boating pond bank raised by between one and three metres, and seven suggestions for pools on the Hampstead side.

These all involve building a new 5.6metre high dam at a hidden patch of damp grassland called the Catchpit, north of the Mixed Bathing Pond.

The City has claimed in recent months that the dams project has been scaled back and that less needs to be done than first thought. But commenting on the shortlist, David Lewis, of the Protect Our Ponds Campaign, said: “It seems they still want to do about as much work as they did originally.”

He added: “If there is a dam to be built, then the model boating pond is obviously the one to be built on.

“But our view is that the whole thing is unnecessary and a complete waste of both time and money.”

The City is asking the public to comment on the latest proposals by August 27.

The options will then be narrowed down and an official public consultation will be launched in November.

The report can be found at www.cityoflondon.gov.uk/pondsproject and comments can be made to pondsproject@cityoflondon.gov.uk or by phone on 020 7332 3847.