Delegates from the public and private sectors gathered in Birmingham to launch the Fast Tracks to Europe Alliance, a group committed to ensuring the rail link stays on track.
National Planning Forum chairman Stewart Stacey told delegates: "If Britain is to be at the heart of Europe, it is neither acceptable that London is on a rusty branch from Brussels nor that our regions are beyond the buffer stops."
The group took action after it was revealed that London & Continental Railways was having difficulty fulfilling the contract to build the proposed pounds 5.4bn route.
The Alliance believes the building of the link and new stations at Ebbsfleet in Kent, Stratford and St Pancras in London will be vital to businesses across the country. It also hopes to secure links from the Channel Tunnel to the West and East Coast Mainline.
The chairman of the Local Government Initiative, Cheshire councillor Derek Bateman, said the project had been mishandled from its inception.
"Changes in route, changes in costs, changes in whether it's public or private sector, changes in the whole rail industry ... the list goes on. I have every sympathy with John Prescott's current dilemma, given the situation he has inherited, and I can only wish John well in climbing out of a deep bomb crater hole, dug by others."