Another conservation group has added to concerns over proposals to build a £42million world-leading research centre next to a Grade I-listed building, saying it will “substantially harm its setting”.

The Victorian Society, set up in 1958 to champion Victorian and Edwardian buildings, submitted strong objections to the Royal Free’s plans to build its new Institute of Immunity and Transplantation on a car park next to former church St Stephen’s in Rosslyn Hill, Hampstead.

In its assessment of the submitted planning application, The Victorian Society, whose patron is the Duke of Gloucester and whose vice presidents include Sir Simon Jenkins, said: “The [former] church is a mature and powerful example of high-Victorian rogue architecture and is considered to be Samuel Tuelon’s masterpiece. We object to the proposed construction [as] it will substantially harm the setting of St Stephen’s.”

It follows similar concerns levelled by English Heritage, which had said the new Pears Building would cause “some harm” to the surrounding conservation area and listed buildings.

The centre intends to bring together academics and clinicians in one purpose-built space to greatly enhance the hospital’s ability to carry out world-leading research and offer pioneering new treatments to patients, including people living locally.

A Royal Free spokesman said: “The proposed Pears Building has been designed by the highly respected architects, Hopkins, in a manner that will be sympathetic to the surrounding area, including St Stephen’s.

“The landscaping of the proposed building will open up the area and improve safety for pedestrians.”

Comments for the application are now closed and a date is yet to be set for when the council will consider the proposals.