Recent legislation UK! It's a criminal offence to attempt the impossible. "Attempting the ImpossibleA person may fail to carry through the offence because it is not possible for her/him to do so. It is necessary to ascertain why the attempt has not succeeded in order to determine if s/he can still be prosecuted for attempting to commit an offence. There is a crucial distinction between what is factually impossible and what is legally impossible (see further Archbold 33-129). Even if it may not be possible to commit the full offence because the factual basis is not present, if the facts had been as the defendant believed them to be, s/he can be charged with attempting to commit the offence in question (see R v Shivpuri [1986] 2 All ER 334). The House of Lords in Shivpuri made it clear that the only kind of impossibility which is relevant to liability is true legal impossibility. Even if the facts were such as the accused believed them to be, then the defendant would still not be committing any offence, having made a mistake about what the law was. If the defendant for example, believed it was an offence to import snuff and does import it, s/he does not commit the offence of attempting to supply a controlled drug, as the importation of snuff is not a crime."
A person may fail to carry through the offence because it is not possible
for her/him to do so. It is necessary to ascertain why the attempt has not
succeeded in order to determine if s/he can still be prosecuted for
attempting to commit an offence. There is a crucial distinction between
what is factually impossible and what is legally impossible (see further
Archbold 33-129).
Even if it may not be possible to commit the full offence because the
factual basis is not present, if the facts had been as the defendant
believed them to be, s/he can be charged with attempting to commit the
offence in question (see R v Shivpuri [1986] 2 All ER 334).
The House of Lords in Shivpuri made it clear that the only kind of
impossibility which is relevant to liability is true legal impossibility.
Even if the facts were such as the accused believed them to be, then the
defendant would still not be committing any offence, having made a mistake
about what the law was. If the defendant for example, believed it was an
offence to import snuff and does import it, s/he does not commit the
offence of attempting to supply a controlled drug, as the importation of
snuff is not a crime."