Ferrovial of Spain on Tuesday said a proposal by regulators to break up its UK subsidiary BAA would lead to poorer standards of services and a delay in the delivery of new runways.

Despite its opposition to the Competition Commission’s findings, its shares were up in early trading as investors hoped that a forced sale of its assets, such as Gatwick airport, could bring relief to the company’s balance sheet at a time when the infrastructure and building conglomerate is struggling to refinance its heavy debt load.