It was once a thriving maritime hub, including for the transatlantic slave trade, but after years of industrial decline, Liverpool's economy is getting a boost from its most famous sons.

"This is the most important house of the most important band of contemporary music," Magical Mystery Tour guide Dale Roberts tells tourists outside the terraced home where The Beatles' Paul McCartney grew up.

McCartney lived at 20 Forthlin Road before he became one of the "Fab Four" -- along with John Lennon, George Harrison and Ringo Starr -- and a worldwide superstar.

The red-bricked property is now run by heritage body the National Trust, as is Lennon's former home at 251 Menlove Avenue. Both sites are regulars on tourist trails for fans of the band.

Like other towns and cities across the UK, Liverpool, a port city in northwest England, is facing a cost-of-living crisis.

Its economy is based on "football and The Beatles", says marketing manager Victoria McDermott, whose employer runs the tour and owns the Cavern Club where The Beatles cut their teeth in the early 1960s.

The city, which last month hosted the Eurovision Song Contest on behalf of 2022 winners Ukraine, is home to English Premier League football clubs Liverpool and Everton.

"It's very emotional," says Graham Biley after viewing McCartney's former home as part of the Magical Mystery Tour, the title of a Beatles song and a surreal 1967 film. 

Part-time musician Biley, 70, is joined by about 40 people on the bus ride, which also takes in Penny Lane and Strawberry Field, which both feature in titles of two of the band's most popular songs.

"Don't be too long otherwise you'll stay stuck in 'Strawberry Fields Forever'," jokes Roberts as he spells out the full title to laughter from the customers.

"The first time I heard The Beatles song 'The Long and Winding Road', I cried," recalls Hiromi Beckstrom, 56, retelling the moment around 45 years later. 

Japanese-born, she travelled from the United States with her daughter Alexandra on what she described as a "pilgrimage".

- 'Four strokes of luck' -

Two world wars, the Great Depression and de-industrialisation plunged Liverpool into a long economic decline.

"But... (then) four things happened," says Roberts. "John, Paul, George and Ringo!" 

It was six decades ago, but "Beatlemania" lives on in Liverpool, where statues of the Fab Four can be found around the city.

Two museums are also dedicated to the band along with countless restaurants, bars and souvenir shops paying homage and generating large sums for the local economy.

Almost half of Liverpool's business tax revenue comes from tourism, local councillor Harry Doyle told AFP.

Beatles-related tourism is worth about £120 million ($152 million) per year and supports some 2,500 jobs, according to local government data.

The rebuilt Cavern Club, meanwhile, welcomes 800,000 fans out of 22 million visitors annually, said McDermott.

Music tourism is a big earner too in neighbouring Manchester, the birthplace of Britpop legends Oasis. 

Glasgow attracts fans of Scottish indie band Belle & Sebastian, while Amy Winehouse devotees pay homage to her statue in the beehive-haired singer's old haunt of Camden Market in north London.

Beckstrom and her daughter are also planning a trip to London's Abbey Road Studios, where The Beatles recorded most of their music.

- Pandemic recovery -

Britain is home to renowned summer music festivals, notably Glastonbury, which opened on Wednesday and is set to attract about 200,000 visitors.

Headline acts include international stars such as Elton John, Cat Stevens, Guns N'Roses and Lana del Rey.

The UK music industry generated £4 billion in 2021 -- still some way behind a figure of £5.8 billion before the Covid pandemic.

Abroad, the United States benefits from fans of Elvis Presley heading to his fabled home Graceland in Memphis, Tennessee, while Jamaica attracts followers of Bob Marley.

Danske Bank chief economist Michael Grahn estimated that the start of Beyonce's world tour in Stockholm last month contributed 0.2 percentage points to Swedish inflation as fans flocked to hotels and restaurants. 

UK official data Wednesday showed annual inflation remained at 8.7 percent in May -- the highest in the G7 -- in part owing to higher booking fees for concert tickets.

Concert venues are also struggling with a steep hike in energy and other bills, after already having to close during the pandemic.

"It's incredibly important that we look after" this musical heritage, said McDermott.

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