Is there light at the end of the Eurotunnel? Bondholders of the undersea rail line linking Britain and France. have approved a plan to cut the ailing company’s debt by more than half. It could bring it back from the brink of bankruptcy. The plan to cut debt to 4.2 billion euros from 9.2 billion had already won the backing of other creditors in November. It paves the way for the Paris Commercial Court to take Eurotunnel out of bankruptcy protection. Britain and France granted Eurotunnel an operating concession in return for financing and constructing the tunnel, which was completed in 1993. But revenues have been unable to recoup the enormous costs.