The head of news at the department of transport has been suspended.

Following the resignation of Jo Moore and the departure of spokesman Martin Sixsmith, Ian Jones, the head of the department's media centre, has been suspended on full pay.

The decision to suspend Sixsmith's deputy was taken by the department's permanent secretary, Sir Richard Mottram "as part of the ongoing leak inquiry".

"This decision was taken this morning by Sir Richard Mottram on the basis of a report on the security investigation which he instigated. He has informed Stephen Byers who took no part in the decision. The security report was submitted on March 1. It has been dealt with solely by officials," said a DTLR spokesman.

Byers told the Commons that a small number of people within the media centre were engaged in a personal vendetta and that an inquiry had been set under way to discover who they were.

News that the latest person to be axed is Jones will come as no surprise to those aware of the complex web of who was who in the "Spingate" row which engulfed the department's media office.

A row broke out over Jones' appointment after it was reported that Jo Moore had tried to block his appointment in order to secure the post for a former colleague.

News of the latest stage in what has become an embarrassing saga for a government that prides its presentational skills drew fresh calls for Byers to resign from the Opposition.

The shadow secretary of state for transport, Theresa May, said the row was another blow to the personal standing of Stephen Byers.

"It further undermines his credibility and shows he is unable to control the civil war that is going on in his department. However, the real victims of Stephen Byers' inadequacies are the travelling public. Whilst he spends valuable time sorting out the chaos he created, he could be improving the railways or concentrating on improving the Tube," she said.

"Stephen Byers has lost the confidence of his department and he has lost the confidence of the travelling public. The only option left is his resignation - then he can stand aside and let someone else get on with the job."