The Times law section on 13th January had a timely article by Iain Harris on annulling marriage, saying the Britney Spears annulment was a rare case.
bq. Nullity is extremely rare. In 2002 just 197 marriages ended with a decree of nullity, compared with 147,538 that ended in a decree of divorce. Over the past 30 years as solicitor in family law, I have dealt with only a handful of nullity cases.
Britney Spears is reported to have been granted an annulment on the grounds that she ‘lacked the understanding of her actions’ (she was apparently drunk). Harris says the English equivalent would be lack of valid consent as a result of duress, mistake, unsoundness of mind or otherwise.
Mind you, if you look at the decree itself, the text goes on to speak about not knowing each other well enough, which is a somewhat different argument.
In English law, there are void marriages, as the article says (void from the beginning) and voidable marriages (they can be annulled but need not be).
In Germany there used to be three possibilities: Nichtehe, Ehenichtigkeit and Eheaufhebung, but it looks as if Ehenichtigkeit was abolished in 1998.