Peers have hit out at controversial plans to build a zip wire tourist attraction across the Thirlmere Reservoir in the Lake District.
Liberal Democrat Lord Greaves said it was a "very bad idea" and would bring "inappropriate commercial intrusion" into the Lake District national park.
Tory former Cabinet minister Lord Tebbit warned the zip wire would be a "highly dangerous impediment" to RAF low-level flying practice.
Communities and local government minister Lord Bourne of Aberystwyth said that as a "live" planning application was currently under consideration by the Lake District national park authority, it would be inappropriate to comment.
At question time, he said that as the plan fell within both a national park and a world heritage site, existing planning policies provided "significant protection".
Lord Greaves said the Government's overriding responsibility to protect this "jewel in the crown" meant ministers should call in the application and "stop it now".
Lord Bourne said the Government recognised the importance of the Lake District but could not comment on the application.
Labour former minister Lord Clark of Windermere said it would be "inappropriate for the tourist industry to see it as merely a way to create another Disneyland".
Lord Tebbit said that while the the preservation of natural beauty should be a high priority, the Government's first obligation was to provide for the country's defence.
The proposed zip wire would be "a highly dangerous impediment" to aircraft and aircrews practising low-level flying, he added.
Lord Bourne said again that he could not comment on the application, which will be considered next month by the national park authority, but confirmed the Ministry of Defence had registered objections.