Have you ever strolled south-west along Piccadilly to Hyde Park Corner and noticed this rather regal building facing out onto Wellington Arch? It's called Apsley House, was home to the 1st Duke of Wellington for years, but also lays claim to having the address 'Number 1, London'.
The original house was built on the site in 1778, for Lord Apsley. Being in Hyde Park, the lease for the land was negotiated from the Crown Estate, and the house was the first one on the north side of Piccadilly. At the time, it was next to the main turnpike or toll into central London, so became known as 'Number 1, London', because it was was the first house you came to once you entered London.
The property's official address today is 149 Piccadilly, Hyde Park Corner, London, W1J 7NT, but rumours still abound that if you posted a letter to 'Number 1, London' it would reach this address. We haven't tried this one, but if you do, let us know how you get on.
Today, Apsley House is a Grade I listed building, owned and managed by English Heritage and open to the public. Check website for prices and opening times.