UK Home Secretary Suella Braverman has said that British citizenship will be blocked to "serious criminals" regardless of when or where the crime took place under the country's tightened norms effective from Monday.

The Indian-origin minister said she is cracking down on the misuse of Britain's nationality system by raising the bar for those applying for citizenship.

The changes override previous rules under which some criminals could be granted British citizenship after a prescribed number of years of around 15 years had passed since the end of their sentence regardless of the type of crime or where it was committed.

"British citizenship is a privilege. Those who commit crimes shouldn't be able to enjoy the breadth of rights citizenship brings, including holding a British passport, voting and accessing free medical care from the NHS (National Health Service)," said Braverman.

"I am cracking down on abuse of the UK's immigration and nationality system, by introducing a tougher threshold so that serious criminals cannot gain British citizenship. This is the fair and right thing to do for our country," she said.

The British government crackdown involves strengthened rules applying to new applications from anyone who has received at least a 12-month prison sentence.

The UK Home Office said it re-affirms the government's commitment to protecting UK borders and ensuring no one with a criminal record can abuse the British immigration and nationality system.

The updated rules are stricter and more specific on so-called "good character" requirements, which are a key condition to be granted British citizenship, and look at whether an individual has observed UK law as well as shown respect for the rights and freedoms of British citizens.

The requirements include factors such as criminal convictions, immigration offending and serious behaviour like war crimes, terrorism or genocide.

According to the Home Office, there will be some exceptions to the stricter new rules, which will be assessed on a case-by-case basis, for example, if someone has mitigating circumstances that support an exceptional grant.

Cases like this could include someone who committed a minor offence a long time ago but has made sufficient, positive changes that they are now considered to be of good character, it noted.

Under previous norms, a four-year prison sentence was the threshold at which a British citizenship application was likely to be refused.

The Home Office said its "toughened-up good character rules" will mean the criminality threshold for British citizenship is in line with the government's wider visa and immigration rules.

PTI