With a subtle but unmissable flourish, Jussi Pylkkänen flicks his wrist fractionally upwards to signal that, unless someone offers him 24 million quid, he is going to bring the entertainment to an end.

“Selling in the doorway at 23 million 500,” he announces, gesturing at the mysterious figure standing at the threshold who has made his presence known with the last bid. “Fair warning to the room at 23 five. Selling at 23 million, 500.” A brief pause as he looks around one last time. “All done.” Bang! The gavel falls with a sharp rap on the Chippendale-designed rostrum. “Sold, for 23 million, 500,000 pounds.”

With commission, the buyer has just spent a total of £26,340,500 on Francis Bacon’s Triptych 1974-1977, the highest price paid for a postwar work of art sold in Europe. The transaction has taken just 80 seconds. And that, according to Pylkkänen, who is the president of Christie’s Europe and tonight’s auctioneer, was a sluggish pace. “Those major lots, you’ve got to slow down. Two bidders on a picture like that, you’ve got to be careful.”

The Bacon sale is the highlight of a record-breaking, but not entirely successful, week in the British art market. More than £400 million of works are for sale this month at the big auction houses in what is regarded as a barometer of the confidence of wealthy collectors at a time of turbulence in the financial markets. The Times followed Pylkkänen through what he would later describe as “the most eventful and high-pressure three days of the year”.

When I go to Christie’s headquarters in St James’s on Monday afternoon he is sitting in his office, which is hung with art waiting to be sold, including an Alfred Sisley landscape, watching clients gathering in the foyer for that evening’s Impressionist and Modern Art sale. “I’m extremely nervous,” he admits. “I’m thinking that in an hour and 40 minutes I’ll be on that rostrum.”

It is a huge week for Christie’s, the highlight being Wednesday evening, when they are selling the Francis Bacon triptych which they expect will break the record for a Bacon and become the most expensive modern painting sold in Europe. “So that should be fun. Might make 35, 40 million.” He bullishly predicts that the sale will be “the highlight of the past ten years in the art market. It’s as significant as when we sold the Van Gogh in ’87 [Sunflowers, which sold for £25 million].

“Freud and Bacon, the two great British 20th-century artists, now come into their own; as expensive as Rothko, Koons, the great American artists. A way to go to get to Pollock level or top of the Warhol market, but they have been elevated to the premier league of the art world.”

Last year at Sotheby’s in New York a Van Gogh failed to reach its reserve, causing panic in the art world. On the day of a big sale like the one tonight, such concerns haunt an auctioneer. “There’s always that feeling at the back of my mind, like going into a finals exam.

“The market will decide tonight whether the estimates that we put on pieces are appropriate, how high individuals want to go. It can can be the mood of that person on that particular night. When you are spending five million, ten million pounds, that’s a very serious amount. The client in the Middle East or Russia who has a bad connection or who’s had a bad day may just decide that now is not the moment.”

He says he is not worried that the credit crunch will deter buyers, because those at the top end of the art market are usually in a position to weather such storms, “and if you’re a collector you have only a lifetime in which to collect. If you want to own a Bacon, or a Bacon triptych, you will look at the painting and say: ‘I have to have this picture. I won’t get another chance’.”

An Impressionist specialist, 44-year-old Pylkkänen is a Finn who was educated in Britain. He has been at Christie’s for more than 20 years, and taking big sales for a decade. One of the skills of the auctioneer is to maintain a steady, brisk pace. “Poise is important. You can get rattled by people splitting bids, people missing bids, or telephone bids making life complicated. Often you are talking a foreign language, on the line to someone on a ski slope.

“I’ve had bidders who were going into tunnels in Venezuela – they get cut off and you have to wait a while, but if you can’t get them back the lot has gone. You wait just long enough not to lose your audience.”

He aims to sell a lot a minute: “A great auctioneer will add 20 per cent to the sale because he or she holds people’s interest.”

We descend through a warren of back rooms and passages for a sound-check in the Great Room. Porters in white gloves carry a Lichtenstein, unwrapped and ready to hang, through the foyer, where clients are beginning to gather. A Russian man is arranging for all Christie’s wine catalogues to be sent to his home in Moscow. Pretty young women in immaculate black suits clack around in heels, clutching catalogues. These are the “Christie’s angels” who will greet wealthy collectors, offer them drinks and canapés and show them to their seats.

As porters bang in a couple of nails and hang Picasso’s Homme Assis Au Fusil, expected to be the big sale of the night, there is a growing buzz in the building. Experts pace up and down making calls to clients. Pylkkänen stages a mock auction for the sound engineers, and racks nerves by soliciting “bids” from the lone reporter present – me, an auction novice.

He goes to study his auctioneer’s book, which holds details of each lot and his scrawled notes of commissioned bids and the names of clients and their representatives who have indicated that they will probably bid.

The sale is ticket-only, with two other rooms also packed with potential bidders in front of auctioneers on standby to transmit their bids to the Great Room. Staff dealing with telephone bidders are corralled on either side of the rostrum. It is an intriguing crowd. Many are obviously dealers, gabbling into phones with hands half-cupped over their mouths. There are well-heeled couples, and lone men whose shabbiness belies the money they must have at their disposal – their own or other people’s. To my right, in row F, is a chap in combat trousers. He wears an unfashionable leather jacket over a rollneck, and carries a battered rucksack. To my left is an elegant young American blonde with her mother. They both note the price of every lot in their catalogues, but show no interest in buying anything today.

The bidding is slow at first, until a Caille-botte does surprisingly well. Pylkkänen's style is gently to entreat his audience to bid: no pressure, but you could be missing the picture of a lifetime. “I’ll take four-two if you like . . . will you give me four five? I can see you’re hesitating. Are you out, Sir? I’m sorry . . .” He leans towards the audience, staring fixedly at one bidder while extending his arm in the direction of another, as if trying to keep them locked in competition.

“Give me one more, Sir,” he gently cajoles. “It’s the lady’s bid against you. All eyes are on you . . . nine hundred . . . is that the killer blow, or will you give me a milion?” Beat. “One million!”

Quite a few lots are not sold because they fail to reach their reserve prices, including works by Degas and Matisse. The big Picasso sells for a sum at the lower end of its £5-7 million estimate. But another Picasso, Femme au Chapeau, with an estimate of £2.5 to 3.5 million, attracts enthusiastic bidding until it stalls at £4.2 million. “Give me 4.3 and it’s yours,” he tells a bidder. Then, just as the hammer seems about to fall, a new bidder – a man two rows in front of me, sitting with his wife – enters the fray with a £4.3 million bid. The price then rises in £100,000 increments as the man takes on a telephone bidder, whispering to his wife at each turn and nodding almost imperceptibly at Pylkkänen, whose gaze is fixed on him like a laser beam.

The man appears to be out as the couple have a last whispered conversation and the room waits. Then a nod and the picture is his for £5.7 million. His wife biffs him playfully over the head with her catalogue. But he is clearly in the mood for buying. He is the underbidder on another Picasso, then buys a Mondrian for more than £2 million, and a sculpture by Julio Gonzalez.

The crowd thins out for the Surrealist part of the sale, and Pylkkänen comes to sit in the audience. He admits that he hadn’t expected that Picasso to make such a price.

It is not possible for somebody to sneeze and accidentally buy a multimillion-pound work of art, he says. An experienced auctioneer is looking for eye contact, for someone with a bidding paddle, and knows when a bid is serious. But he has had to stop people from waving, and confusion can arise. When someone seated just behind me is bidding, there is a terrifying moment when I think the auctioneer is looking at me. Later, a woman becomes similarly convinced that she is about to buy a painting for £350,000, and shouts: “Not me! Not me!”

By the end of Monday evening Pylkkänen is “very happy” – the night’s £105 million total is second only to a Christie’s sale last year in the league table of highest totals for an auction in Europe. American buyers stayed away and, unusually, a quarter of the lots did not sell. But the overall tally, and the fact that ten pictures sold for about £3 million or more, is enough to convince him that the market is still “very strong”. He repairs to Soho House with a group of colleagues to celebrate.

That second-highest sale placing lasts for only 24 hours. Then a Sotheby’s sale, boosted by Russian buyers, takes £117 million.

The auction houses have long been rivals, although at Christie’s they like to point out that Sotheby’s is a relative newcomer to art, having been concerned primarily with selling books until the end of the 19th century. The two houses were inextricably linked in a price-fixing scandal a few years ago but Pylkkänen says that, with a new management team in charge, that is all behind them.

It’s a glitzier crowd for the Postwar and Contemporary Art sale on Wednesday. More fur, more facelifts, more Russians, a scattering of Chinese. Several pictures fail to sell, prompting mutterings. A Damien Hirst butterflies picture doesn’t reach its reserve; nor does a Warhol self-portrait. But US interest helps a Jean-Michel Basquiat go for £6.5 million, the second highest auction price for the artist. A Bridget Riley spot painting goes for £1.4 million, a world auction record for the British artist.

The man who bought the Picasso on Monday is up to his old tricks, swooping in just before the hammer to scoop an Yves Klein. Pylkkänen had already spotted him in the crowd: “You get that sixth sense. You just feel the burning eyes and take the bid.” When the bids are racing up he is flamboyant, as if conducting an orchestra. When something is not selling he dispenses with it brusquely in seconds.

The purchaser of the Bacon is an agent of a collector. The price does not beat the previous Bacon record of $52.68 million (£27 million) set in New York last year, and is nowhere near the £40 million that Pylkkänen had mentioned on Monday. He doesn’t come to the press conference. When I find him in his office, he says that is because he didn’t want to steal the thunder of those who had organised the sale. Although the Sunflowers sale was 20 years ago, when £20 million was worth rather more than it is today, he says he is “very proud” to have broken the record.

In fact he had known earlier in the day that the record for a Bacon was unlikely to be broken: “I spoke to a small group of significant collectors. They gave an indication of what sort of level they would go to.”

As for the 30 per cent of lots that didn’t sell, he admits now that the economic situation may have played a part. Then he adds: “If you were honest about our sales, they had weakness in the middle range. We have a very knowledgeable audience.”

In the two evening sales led by Pylkkänen, Christie’s has sold £200 million of art. He opens a bottle of champagne and we watch the last 15 minutes of the England match. Game over, he drains his glass.

“The art market is full of myth. But when you come and see it, it’s transparent. There’s no smoke and mirrors. You put up a decent picture, ask ‘How much do you want to pay for it?’ and off you go.”

Jussi’s top tips for buyers

1 Don’t think you have to be a millionaire.
We offer works in more than 80 collecting categories with prices starting at £250. Christie’s South Kensington has an average price of £1,000 and offers a huge range of furnishings and objects from the practical to the downright quirky (furniture, picture, silver and ceramics sales are complemented by posters, wine and fashion).

2 Research an object.
If you can, visit the presale exhibition and see it for yourself. Catalogues are available a month before the sale. All views are open to the public three or four days before the auction, and everybody is welcome to browse. You can research any object online via www.christies.com .

3 Never be afraid to ask questions.
Specialists are always on hand to answer anything – about the item, its condition, its estimated price, the market in general, the auction process.

4 Set your limit.
When preparing for an auction, set your upper limit, as we have known people to get a little carried away at the time – although it is rare that people regret their purchases.

5 Most of all, buy with your heart.
More and more people look at art as an asset class. We don’t really encourage buying for investment. You should buy art that you love and that you want to live with.

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