Auction reveals the secret life of Spike Milligan

It sounds like one of the jokey stories he would tell in a poem or novel. When a wrecking ball sliced a nearby Victorian block of flats in two, Spike Milligan spotted a grand piano left in a disused apartment. Approaching the foreman of the building site, he bribed him with a fiver to hand over the instrument.

"The money did the trick. The piano was lowered to the floor in a net, another £10 to have it transported to me home – and voila! I had a grand piano." But a mere work of humorous fiction this was not – it actually happened. And that very 1883 Broadwood Grand, having been established in the Milligans' home, was played every morning by none other than Paul McCartney, a neighbour in Rye in East Sussex, who would let himself in to wake up his friends by playing the piano.

The musical instrument is one of an array of personal effects which are being sold by Milligan's third wife, Shelagh, who is moving into a smaller home which does not have the space to hold the myriad of items that her late husband collected.

So Milligan, who wrote the lines "With hand signals/ Or polite cough/ He bid twenty-five million/ For a Vincent Van Gogh/ For that sort of money/ I'd chop my ear off" in the five-line poem "Auction Stations", is himself going under the hammer.

In the first major auction of his personal effects since his death from liver failure in February 2002, a previously unseen collection of personal books and notes (including a handwritten copy of the above poem) will go on sale, alongside furniture, paintings, manuscripts, photographs and recordings that belonged to the comedian, at Bonhams on 25 November.

"I just don't have the space in my new house to put everything," said Shelagh. "The alternative is that I carry on paying these huge storage bills and everything just sits there rotting away. But I can't pretend I'm going to find it easy. When we were cataloguing various items for the sale, I went to the store and it felt as if our whole life was laid out in front of me."

Items expected to fetch the highest prices at the wider celebrity-themed auction include the yellow Reliant van from the BBC's popular television series Only Fools and Horses and a tasselled waistcoat once worn by Elvis Presley. But it is Milligan's personal artefacts that are causing the greatest excitement among collectors because of the astonishingly personal portrait they paint of the comedian's life.

As well as the piano, other lots reveal just how close the comedian was to all the members of the Beatles, who were fans of The Goon Show, Milligan's radio show that revolutionised British comedy in the post-war era. Beatles-related memorabilia include a banner with the words "Peace" and "Love" given as a Christmas present by George Harrison and a book on trauma therapy signed by John Lennon and Yoko Ono.

Other lots allude to the more anarchic side of Milligan that characterised much of his comedy in a career spanning more than five decades. A prolific note-writer, Milligan loved to leave chaotic and amusing missives – a note on his grave in East Sussex, for instance, reads "Duirt mé leat go raibh mé breoite", Gaelic for "I told you I was ill".

A collection of scribblings aimed at guests who visited his home are expected to fetch up to £150. One note left for taxi-drivers reads: "Driver please don't knock – I'll be out at the appointed time"; another for smokers reads: "No smoking. We are trying to give up lung cancer" and a typically self-deprecating note that was often left on his front door as a warning to guests simply reads "Sorry for being me – I don't know how to be anyone else".

Stephanie Connell, a specialist in entertainment memorabilia at Bonhams, said she expected the auction would be popular despite the current economic circumstances because many of the lots are relatively inexpensive. "With entertainment memorabilia you will always have a fan base who are willing to buy items and they'll come up with the money regardless of the financial conditions," she said. "Most of the lots are also not going for an especially large amount of money. This sale offers a unique opportunity for fans of Spike Milligan to obtain a personal memento from a sadly missed legend of British comedy."

But although he was regarded as one of the greatest British comedians of the 20th century, Milligan was also prone to bouts of severe depression. In an interview with Bonhams Magazine, Shelagh recalled how one of the world's funniest men would often "retreat into his room and stick this postcard on the door saying 'Fuck off'".

She recalled: "There were times when I was wounded by things he would say to me, things he did. But on the whole I gave as good as I got."

Lyrical lots: Milligan memorabilia under the hammer

TOW PATH

"In Manchester Square/ Where there's nowhere to park/ If you do then along comes A Warden or Nark/ And they tow your car/ To Rochdale pound/ Three times a day/ If you leave it around.

"No more Manchester/ Then for me/ If they want me again/ I'd have to be/ Dead as a door nail/ Strapped to a bike/ Then they can tow me/ Wherever they like!"

(Inspired after being towed away three times in a day in Manchester)

Mountain

"I'm going to eat a mountain/ It shouldn't take long they say/ I'll slowly eat that mountain/ Bit by bit every day"

The poet of Dumbwoman's Lane

(written by Paul McCartney to Spike Milligan)

"The voice of the poet of Dumbwoman's Lane/ Can be heard across the vallies of sugar-burned cane/ And nostrils that sleep through the wildest of nights/ Will be twitching to gain aromatic insights.

"The wife of the farmer of Poppinghole Lane/ Can be seen from the cab of the Robertsbridge train/ And passengers' comments will frequently turn/ To the wages the wife of a farmer can earn.

"The poet of Dumbwoman's Lane sallies forth/ He is hoping for no one to see."

Extract of a speech to Chelsea Arts Club, May 1982

"My lords, ladies and gentlemen, and that swine the chef. I am here a) because of an invitation and b) hunger. The invitation came from a Miss Coil, whose grandfather invented it... I asked her why I was to be honoured as after-dinner speaker – she said 'well we'd run out'. I said 'of speakers?' She said 'no – money'. I said 'I understand as I've heard that people are being paid £3 to come here and £5 to eat the dinner'."