But not until last October did the practice come under legal challenge.

Whether it may issue the shares is under legal challenge.

These arrangements are not under challenge, at least for the moment.

By the time I met him in mid-1994, though, his authority had come under serious challenge.

The total amount under challenge is, I understand, a sum in the region of £1.8m.

But as the play opens, that view of himself is under serious challenge.

America is under serious challenge now, in another struggle we must win - and will.

But even that title may be under challenge from the former president with whom he served.

Now, access to other sources of information has brought the controlled media under challenge.

His authority to demand the return is also under legal challenge.