Scottish secretary Helen Liddell has insisted that her role in government is "a fairly critical one".

The minister, who has been accused of filling her diary with French lessons and foreign trips, has claimed she has a vital part to play in post-devolution Scotland.

Quizzed, however, about whether her post would survive as devolution beds down, Liddell said the issue was "a matter for the prime minister".

Interviewed in the Guardian, the minister, who is also facing the loss of her seat in the Scottish boundary review, said she had "still got a career in front of me".

"But you know, people who try to build careers around the absolute certainty of being elected often come unstuck," added Liddell.

The Lords constitution committee has also called for separate cabinet posts for Scotland and Wales to be scrapped.

She conceded that it had not been plain sailing since the creation of the Scottish parliament.

The death of Donald Dewar - who she described as the "father of devolution" - robbed the Holyrood parliament of someone who "was also running a sort of master class in how to do the job".

And she warned that public confidence in politics should not be allowed to sink any further.

"I think there is a climate around at the moment which disturbs me, that it is fashionable to be cynical about politics and politicians," said the Airdrie MP.

Calling for a more honest political debate, Liddell said: "I'm not exactly on the softer and gentler side of the political spectrum, but some of that is because we have a system that doesn't allow people to admit that perhaps they don't have a view on things.

"We have a system where we are not allowed to explore some of the philosophical and theoretical arguments around issues, and I think that's a bit stifling."