The chairman of 51m - an alliance of 18 local authorities opposed to HS2 - has warned that the project will not universally benefit train services:
Many towns and cities will be shocked to discover that they will actually receive a poorer train service if HS2 is built.
Stations such as Toton Sidings and Meadowhall are far from city centres.
West Coast Main Line and Midland Main Line services to many existing stations are certain to be reduced.
He added that the line would "blight the lives, property and businesses of tens of thousands of people".
More top news
Major changes are expected to be unveiled at the secretive state's rare Congress meeting - but journalists were shut out as it got underway.
The Welsh reality star has suffered a debut election defeat - and revealed he had a tough time on the campaign trail.
Labour strongholds tended to remain so - apart from a major loss for the party in Dudley.