Controversial development plans for a much-loved heritage attraction are set to be unveiled next week.

On Tuesday (October 6), the Waltham Abbey Royal Gunpowder Mills Charitable Foundation (GMCF) will showcase plans for the attraction from outdoor education and adventure holiday company PGL.

The exhibition, which is open to members of the public, will reveal how large parts of the park could change although planning permission is yet to be officially submitted.

Proposals for the site, which contains over 20 listed buildings and a site of special scientific interest over 73 acres, include creating a new outdoor activity centre for children with guest accommodation, creating spaces for 850 children and room for around 100 staff and teachers.

A spokesman for PGL said: “The PGL proposals would be entirely complementary to the existing visitor attraction, which would remain, albeit on a reduced area of the site.

“The existing visitor facilities and main exhibition on the Island Site would remain and it is hoped that a new light railway would link this part of the visitor attraction with the area of the scheduled ancient monument in the north, which contains the majority of the historic structures and heritage features of this important site.”

Other proposals include a new lake for water activities, zip-wires and climbing walls, and a target range.

PGL’s plans have been persistently opposed by some in Waltham Abbey, with a website called Save the Royal Gunpowder Mills set up in December last year.

The website claims the GMCF’s plans “threaten almost everything that has been achieved by staff and volunteers, grants of public funds, private donations and commercial income since 2001.”

Public access to listed buildings, exhibition space for valuable artefacts and historic buildings would all be lost under the plans, the site claims.

However, the PGL spokesman claimed: “There is clear synergy between the existing visitor attraction and the PGL proposals – especially given the nature of the outdoor recreational uses proposed and the location of the site within the Lee Valley Park.”

Detailed draft plans will be on show at the Royal Gunpowder Mills between 2pm and 8pm on Tuesday.