Then she became very close to Nick Clegg. At the first hustings of the 2006 leadership campaign Nick would not let Ming Campbell, the candidate he was promoting, out of his sight and Sarah would not let Nick out of hers.
Nick Clegg soured the relationship first by sacking her as a minister. Now this evening comes news that Sarah Teather is to leave parliament at the next election.
In an interview with the Observer she says that she cannot support Coalition policies on immigration and social security - though she was less vocal about her opposition when she was a minister.
She tells Toby Helm:
For periods over the past year, Teather thought she might be able to operate alone as a rebel within but, this summer, she took four weeks off, switched off her phone and just thought hard about the future. A fortnight ago, she finally concluded that she hadn't the energy or the will to go on without support, and she felt there was not enough there.But that tells only half the story.
There are plenty of people in the party who agree with Sarah on immigration and social security. The reason she feels isolated is that she failed to support equal marriage, with the result that many who are her natural allies no longer trust her.
And Toby Helm does not mention that in his article.