Civil war has broken out at National Express with its major-shareholding deputy chairman saying the stricken train and coach group's management do not know what they are doing.

The fear is that the Cosmens, the Spanish family that owns 18% of National Express, may not now back the train and coach group's plan for a rescue rights issue of up to £400 million.

In highly-damaging criticisms for National Express's chairman John Devaney, his deputy Jorge Cosmen said: “We have serious concerns about the absence of a well-defined strategy to address the company's broader and longer-term issues.”

In a statement released to the Stock Exchange, Cosmen went on to criticise Devaney's decision this week to reject arch-rival's Stagecoach merger offer saying National Express did not give it “sufficiently full and thorough assessment”.

The Cosmens, who run National Express's Spanish operation, made no comment on whether they would now support the rights issue, which National Express confirmed it would embark upon from possibly as early as next Monday. Sources say the Cosmens' previous support for a rights issue had always come with a “within certain parameters” caveat.

At issue appears to be Stagecoach's plans for a merger and disposals programme at National Express, which the Cosmens have now made plain they supported.

In the absence of National Express's board coming up with a blueprint for the company's future, the Cosmens are understood to believe a rights issue is not a “silver bullet” that will save a business creaking under £1 billion of debt.

Analyst Andrew Fitchie at broker Collins Stewart believes the row has broken out because of the self-interest of Devaney's board and his corporate finance advisors Merrill Lynch and Morgan Stanley.

“One could argue the company's brokers and advisors would be best served by generating fees through an equity raise,” said Fitchie.

“And the executives will keep their jobs if they pursue an independent future. Turkeys don't vote for Christmas.”

In a statement refuting Cosmen's claims, National Express said the Stagecoach merger could not have gone through before 31 December, a key date when National Express is likely to be in breach again of its banking covenants if it does not get a rights issue away.