The reason why Sir Paul McCartney sent a green submarine to Liverpool

Beatles fans have been intrigued by a giant green submarine which has appeared in central Liverpool.

The boat has been teasing the publication of a new picture book by Sir Paul McCartney.

Grandude's Green Submarine follows on from the adventures of Sir Paul's 2019 New York Times bestseller Hey Grandude!

• Watch an exclusive clip from the recording session for the audiobook

> Liverpool dad's bus stop chat with Sir Paul McCartney

People queued up outside Waterstones in the Liverpool One shopping centre over the weekend to get hold of a copy of the book and see the sub docked in the store.

Despite the Beatles singing about a Yellow Submarine, Sir Paul has revealed he always envisioned more than one vessel.

The singer and musician explained how he wanted to reintroduce the idea for the book in the form of a green submarine, which also gives a nod to the environment.

Shoppers can see the sub for the rest of Monday, when Sir Paul will then donate it to Alder Hey Children’s Hospital and Charity.