A pop star who was told she was "not British enough" to enter The Brits and the Mercury Prize has won a reversal in the awards' eligibility rules.

Rina Sawayama was told she could not compete for the prizes last year, because she was not a British citizen.

The singer, who has lived in the UK for 26 years, has now won the right to compete, after meeting award bosses.

Under new rules, artists who have been resident in the UK for more than five years will now be eligible.

Sawayama holds indefinite leave to remain in the UK, but retains a Japanese passport to maintain ties with her family, including her father, who live in her country of birth.

As Japan does not allow dual citizenship, she cannot have a British passport. That meant her critically-acclaimed debut album was ruled ineligible for last year's Mercury Prize.

"It was so heartbreaking," Sawayama told Vice last year. "I rarely get upset to the level where I cry. And I cried."

"All I remember is living here," she continued. "I've just lived here all my life. I went to summer school in Japan, and that's literally it. But I feel like I've contributed to the UK in a way that I think is worthy of being celebrated, or at least being eligible to be celebrated."

The hashtag #SawayamaIsBritish trended in the UK shortly after her interview with Vice was published.

The singer subsequently met with the BPI, which organises both the Brits and the Mercury Prize, and convinced them to review their criteria.

"I'm over the moon to share the news that, following a number of conversations, the BPI has decided to change the rules," Sawayama posted on Instagram on Wednesday.

"Starting this year, artists (like me) will be eligible for nomination even without British citizenship."

The Brit Awards confirmed the change to the BBC, saying it would apply to all its award categories, as well as the Mercury Prize.

Artists will now have to meet one of three criteria to be eligible:

1. They were born in the UK.

2. They are a UK passport holder (this includes those that hold more than one passport).

3. They have been permanently resident in the UK for more than five years.

The change means Sawayama will be eligible for this year's Rising Star award, which recognises up-and-coming talent.

However, she will not be able to compete in the main categories - including best British female and best album - as her record did not chart in the Top 75.

Sawayama has previously benefitted from funding from the BPI Music Export Growth Scheme, a grant that supports and celebrates British musicians, and her album is littered with references about growing up in London.

The record, which skilfully blends millennial pop and R&B with elements of nu-metal, was one of the best-reviewed new releases of 2020, with an average score of 89% on the review aggregation site Metacritic.

Many publications, including the Guardian and the NME, named it among their best albums of the year; and it took 11th place in the BBC's "poll of polls", which combined the year-end lists from 35 influential newspapers, magazines and blogs.