Shouldn't the ' I swear by almighty God to tell the truth ect, ect be changed to something like ' I realise that if i am ever found out to have lied in this court I am liable to have my assets seized, or a fine of € 50,000 or both, or aminimum of 5 years in prison.

It seems to me that the whole concept of getting people to swear an oath to God is unrealistic, given the fact that many of todays witnesses are non believers

True but sure you may as well keep it just for traditions sake.

Take out the three offending' words "by almighty god". Job done!

Wouldn't it be interesting if someone did refuse to take the oath on the grounds that they did not acknowledge the existence of god.

If you are an un-believer then you can choose to make a declaration, rather than take an oath.

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Fiat iustitia, et pereat mundus

Tantum religio potuit suadere malorum

You can "affirm" if you so wish.
It has no reference to God.

Did you try googling before opening the thread?