Historic England has has warned that controversial plans for allotments in Syon Park could "harm" the Grade I-listed estate.

The Duke of Northumberland has applied to build 127 homes on the Park Road allotments site , across the road from Syon Park, in Isleworth.

He has offered to rehouse gardeners within the park's grounds, close to the distinctive Lion Gate entrance in London Road.

But allotment holders are fighting his proposals and an online petition has more than 1,060 signatures.

'Development would change character of estate's landscape'

Now Historic England, the conservation body responsible for managing the national register of listed buildings, has waded into the row.

"The development of allotments within this part of the registered park and garden would very obviously change the character of the landscape and thereby harm the contribution it makes both as part of the park and also as part of the setting to the gate," the organisation said.

The comment from Historic England's Helen Durrant is quoted in a letter submitted to Hounslow Council's planning department by gardeners opposing the proposed new allotments.

How the new allotments within Syon Park would look

There is also some dispute over how many of the allotment holders at the current site would be prepared to move to a new 37-plot site within the park.

Allotment holder Sharon Probets, who started the online petition, says no more than 10 out of 43 have accepted the offer.

But Northumberland Estates, which manages Syon Park, says the majority of current allotment holders have expressed an interest in a new plot.

'Dispute over proportion of allotment holders willing to move'

Ms Probets said: "We were shown three options within the park and the favourite was just over the road from the current site.

"I think the main reason they don't want to put us there is because it would interfere with their commercial events in the summer, when they have marquees there offering hospitality."

A spokesman for Northumberland Estates said: "The proposals offer an excellent location for both existing and new allotment holders and bring the facilities within reach of a much wider catchment area accessible to both Isleworth and the wider Brentford area.

Lion Gate at Syon Park would be renovated under the plans

"In contrast to the previous unused and overgrown plots at Park Road, we expect the new site to be fully utilised benefiting many more people overall."

The Duke wants to build 119 flats and eight houses on the existing allotments, which would be rented out to raise money for the park's upkeep.

Campaigners opposing the planned homes recently registered the current allotments site as an "asset of community value".

But the estate says this protected status has no impact on the proposals as the Duke is not planning to sell the land.

WHAT THE ESTATE SAYS

  • New homes would help meet the need for housing in the area
  • The plans will help fund the "vital" restoration of the 250-year-old, Grade I-listed Lion Gate
  • There is a history of market gardens along London Road
  • The new allotments would be on land which is currently used for grazing and offers a "more favourable aspect" for growing
  • A "great many" existing allotment holders are willing to move

WHAT CAMPAIGNERS SAY

  • Park Road allotments are a "wildlife haven" which should be preserved
  • The land earmarked for the new allotments is not used for grazing
  • The application for allotments is a temporary one, and there is no guarantee about how long gardeners will be able to use the land
  • Upkeep of Lion Gate is the Duke's responsibility regardless of what happens
  • A "minority" of allotment holders have taken up the offer of a new plot