Minister on warpath over leaked letters

Several prosecutions are likely following investigations into leaks of letters written to the Prime Minister by Liam Fox, the Defence Secretary predicted yesterday.

Dr Fox's private thoughts have twice made their way into the public domain recently – first over the impact of spending cuts on morale in the forces and then when he urged a rethink of spending on overseas aid. Fellow ministers have been suspicious about the origin of the leaks, as they will have burnished Dr Fox's credentials with the Conservative Right.

But he stressed yesterday he did not know who was responsible – and would not even rule out a Cabinet colleague being behind them. "You never know, and that's the whole thing with leaks. First of all they're unprofessional and they're unethical, and in being unwilling to stand up and argue the case publicly they're also cowardly. It's a culture I think that's emerged in recent years, which is hugely regrettable," he told BBC1's Andrew Marr Show.

In his leaked letter last September, Dr Fox warned Mr Cameron that defence cuts could "seriously damage troops' morale", while this month he objected to plans to spend billions of pounds more on aid.

The Defence Secretary yesterday warned that ministers would be less likely to put things on paper because of the fear of leaks. "Therefore there is less transparency... which I think is an ethical problem in the longer term," he said.