This week Oxford East MP Andrew Smith was tipped to take over as Transport Secretary, but he is busy doing another job -- standing in for Gordon Brown and running the national economy.

One consequence of the Chancellor and his wife's tragic loss of their ten-day-old baby daughter, Jennifer Jane, is that the Treasury Chief Secretary has had to step in to fill the breach.

When Mr Brown left Whitehall on paternity leave, it was expected to be a brief absence followed by a cheerful return.

But now Mr Smith seems likely to be in charge for longer as Mr Brown and his wife deal with their unimaginable grief.

Treasury insiders are quite happy with Mr Smith as a stand-in -- he has developed a reputation for competence and skill while acting as the Chancellor's number two and was already in charge of the main business of the moment. The comprehensive spending review is due to be announced in the summer setting out public expenditure plans for the next three years.

Before Christmas, Mr Brown set out the broad outline of his March budget and will be back in plenty of time to put the finishing touches to his annual financial package.

Mr Smith and his wife Val will take the day off today to attend Jennifer Jane's funeral in Scotland.

Mr Brown and his wife, Sarah, are very appreciative of the support shown to them by the Smiths, said Treasury officials.

The news that Mr Smith, widely seen as one of Whitehall's safest pairs of hands, is in charge has been welcomed by Oxfordshire Tories Tony Baldry and David Cameron.

An aide to Mr Smith dismissed any talk of a move to transport to replace embattled Stephen Byers, and said Mr Smith was fully occupied with his current task.

The aide said: "Stephen Byers is a first class transport secretary. Any talk of Andrew Smith doing that job is speculation. The government has a ten-year transport plan of investment and, step-by-step, road and rail is beginning to improve.

"In any case, he is very busy at the moment taking on some of the Chancellor's duties at the Treasury -- as well as his own.

"We only wish the circumstances were better for Gordon Brown and his wife. We are all devastated by the death of their baby daughter."

Banbury MP Mr Baldry said: 'I've no problems with Andrew running the economy. I think he is rather good news and well up to the job."

Witney MP Mr Cameron said: "I don't imagine there will be any major changes of policy.

"Most things seem to be decided. I am sure he can keep the ship steady.

The only jarring note was struck by Liberal Democrat MP for Oxford West and Abingdon, Evan Harris, who said he did not imagine there would be any improvement in increasing investment and reducing Treasury meddling in public services while Mr Brown was on leave.