Has someone been pushing any buttons on the dash? They may have turned the traction control off by mistake, though that normally re-sets itself when you re-start the car.
Have you had new tyres fitted, or any brake work done ?
Check all tyres are the same size and that the pressures are correct, check they all have similar tread depth.
If there's nothing obvious you'll have to get it plugged in to decent diagnostic equipment to find where the fault lies.
It doesn't have to be a Vauxhall dealer who checks it, but it might be better to use them.
Independent workshops may be cheaper, but Vauxhall diesels are notoriously choosy about which diagnostic machines they will"talk" to, they are best checked with Vauxhall's own "tech2" system.
vaux, December 2009
