Gareth Jones follows Beatles expert Richard Porter on his guided tour of London visiting the places made famous by the biggest band in the world.

'Well hello everyone and welcome to the Beatles 'In My Life Tour'. My name is Richard and I'm your guide for this morning. Well we're starting right here at Marylebone station, because this is where the Beatles filmed the opening scenes for their first film, A Hard Days Night.'

So begins Richard Porter's Beatles walk. Any fan worth their weight in limited edition vinyl and Sergeant Pepper memorabilia will tell you that back in the sixties the Beatles were bigger than Jesus. Forty years on, in London on a cold wet day, the Beatles are still as popular as ever; mind you on the Fab Four walking tour there's not a Liverpool accent or mop top in sight.

"Ya I like the Beatles, I remember them from the sixties, I like come together, I want to hold your hand'" says Anoushka, a Russian tourist. "They have an excellent sense of rhythm and music," says an excited Sandra from Philadelphia. "My school mates used to have portraits of Paul McCartney on the wall," adds Anoushka. "It's so rare that a band can string together two hits in a row but to have as many hits as the Beatles means that there is genius behind it," interrupts Sandra.

But Richard Porter is the veritable pied piper of Beatle mania. He's an encyclopaedia of all you never really wanted to know about the Beatles and is current holder of the 'Beatles Brain of Britain' title. "Some people say that they have been wanting to see these places for the last thirty-five years and are just really grateful," he says. "Just after I started doing the tours, I had these guys who had come all the way from East Germany and when they finally got to Abbey Road they were really overcome. It was a symbol of freedom for them."

Our tour continues. "The first of the Beatles to live here at 32 Montague Square was Ringo Starr", says Richard. "He moved in early in 1965 and later Paul McCartney did lots of work on songs like 'Eleanor Rigby' down in the basement".

We ricochet past the places where 'A Hard Days Night' was filmed, stop briefly at the house where John and Paul wrote, 'I Want To Hold Your Hand' and rest up red faced and panting at the Apple Building. While Liverpool has The Cavern Club, Strawberry Fields and the original Penny Lane, London has plenty of Beatle pilgrimage sights too.

"The big sites, the places where they hung out and where they did things, that's the stuff that you really want to see not the stuff that's in Liverpool," says rock critic David Stafford, "You're not talking necessarily about music, you're talking about history. The Beatles did change the world in many many different ways".

There's no stopping Richard. "This is the site of the Beatles first Apple project, their shop here on Baker Street simply called Apple".

'There are places I remember though some have changed' sang John Lennon in1970. The Apple building is now an employment agency and the Baker Street phone box from 'Help' is long gone. But it doesn't stop the fans turning out.

"It is a shame that so many things look different but you look up and you know that they were playing there. You can just imagine it at the time." muses Sandra.

But when the rain comes we take shelter and exercise our vocal chords. 'Let it Be' sings Sandra, "Words are flowing out like endless rain into a paper cup" croons Trevor.

Then it's on to the final stop. "So here we are at Abbey Road Studios, where the Beatles recorded virtually every song. In fact they recorded one hundred and ninety one songs here," says Richard.

This is the Mecca for Beatles fans - the EMI studios on Abbey Road. And particularly the famous zebra crossing featured on the cover of the 1969 'Abbey Road' album. The traffic backs up as the pilgrims clamour to get The photograph to impress their friends. OK now we are about to walk across the famous Abbey Road Crossing, one of the most famous Beatles sites in the world. How are you feeling? Are you excited? - 'Yes! Even though I've seen it two or three times before, I feel like kissing the ground you know!'

'Well I hope that you've enjoyed yourselves on our London Walk today, thanks a lot for coming,' says Richard.

The group have had 27 UK number ones. 'She Loves You' was the biggest single in British pop history and the back-catalogue generates millions. The Beatles still have the power to make schoolgirls cry and grown men go weak at the knees. For our final comment I turned to, Trevor, die-hard Beatles fan from Nantucket.

"It's more than music, it's bigger than music; it's larger than the world. What I feel for the Beatles is awesome it's out of this world."