+xFirstly, what the UK home office and UK media don't mention is that the current UK system for non-EU visas (which s the one Priti Patel wants to apply to EU after the Brexit transition period), has a 10 year rehabilitation period for anyone with a custodial sentence between 12 months and 4 years. If the EU were to reciprocate on a like-for-like basis, at least that provides a glimmer of hope for another segment of ex-offenders.
Secondly, my personal opinion is that the EU are unlikely to amend ETIAS rules just for one country i.e. UK. At least the EU focuses on the types of crime (ETIAS has a list of 'serious offences') and not simply the sentence, so if the UK ends up under that regime, again the majority of ex-offenders will be OK.
But how are 'serious' offences defined. In the official ETIAS proposal, they list the following
'serious criminal offences' means the offences which correspond or are equivalent to those referred to in Article 2(2) of Framework Decision 2002/584/JHA, if they are punishable under national law by a custodial sentence or a detention order for a maximum period of at least three years.
participation in a criminal organisation,
terrorism,
trafficking in human beings,
sexual exploitation of children and
child pornography, illicit trafficking in narcotic drugs and psychotropic substances,
illicit trafficking in weapons, munitions and explosives,
corruption,
fraud, including that affecting the financial interests of the European Communities within the meaning of the Convention of 26 July 1995 on the protection of the European Communities' financial interests,
laundering of the proceeds of crime,
counterfeiting currency, including of the euro,
computer-related crime,
environmental crime, including illicit trafficking in endangered animal species and in endangered plant species and varieties,
facilitation of unauthorised entry and residence,
murder, grievous bodily injury,
illicit trade in human organs and tissue,
kidnapping, illegal restraint and hostage-taking,
racism and xenophobia,
organised or armed robbery,
illicit trafficking in cultural goods, including antiques and works of art,
swindling,
racketeering and extortion,
counterfeiting and piracy of products,
forgery of administrative documents and trafficking therein,
forgery of means of payment,
illicit trafficking in hormonal substances and other growth promoters,
illicit trafficking in nuclear or radioactive materials,
trafficking in stolen vehicles,
rape,
arson,
crimes within the jurisdiction of the International Criminal Court,
unlawful seizure of aircraft/ships,
sabotage.
3. The Council may decide at any time, acting unanimously after consultation of the European Parliament under the conditions laid down in Article 39(1) of the Treaty on European Union (TEU), to add other categories of offence to the list contained in paragraph 2. The Council shall examine, in the light of the report submitted by the Commission pursuant to Article 34(3), whether the list should be extended or amended.
So in terms of types of offences it is a wide range, but the key threshold is a sentence of 3 years or more.