TONIGHT the worlds of high finance and horticulture will collide at the most popular fixture in the City year: the Chelsea Flower Show charity gala.

BSkyB chief executive Jeremy Darroch was spotted eyeing up garden sheds at last year’s Chelsea preview, while Topshop boss Sir Philip Green – known in the City as “PG” – is also a regular at the UK’s most high-powered garden party.

“There will be a terrific turnout,” said Robert Swannell, chairman of M&S (below), ahead of his confirmed appearance at this evening’s sold-out gala near Sloane Square. “For me it is always a particular pleasure as my wife and I share a keen interest in gardens.”

Swannell and his wife, both trustees of the Kew Foundation, will no doubt make a beeline to the Kew show garden. However, other City names will gather around the Royal Bank of Canada’s New Wild Garden and M&G Investments’ M&G Garden, billed as “a modern take on the traditional kitchen garden”.

But never mind the planting. Who is actually invited to tonight’s garden extravaganza, where 5,000 guests will be served champagne and canapes before 1,000 sit down to dinner in various corporate-hosted tents?

The Royal Horticulture Society refused to give details of the guest list, but it is a safe bet that the senior executives of M&G Investments, the lead sponsor of the gala and the show, will have a strong presence.

So that’s M&G Investments’ CEO Michael McLintock and its owner Prudential’s group CEO Tidjane Thiam accounted for. Moving on to the bankers, The Capitalist hears Lazards’ London chief executive William Rucker is expected, as is Marcus Agius, group chairman of Barclays – apparently he and his wife are both “great flower lovers”.

Simon Mackenzie-Smith, investment banking grandee at BoA Merrill Lynch, is taking a party, while Alison Carnwath, chairman of Land Securities, JP Morgan Cazenove chairman David Mayhew, Standard Life chairman Gerry Grimstone, and Lloyds Banking Group chairman Win Bischoff are also attending.

Throw in M&S CEO Marc Bolland, Tesco’s new chairman Sir Richard Broadbent and David Wormsley, the head of UK investment banking at Citigroup who is advising on Glencore’s £60bn IPO alongside Morgan Stanley and Credit Suisse, and you have a dynamite combination.

Which could become even more explosive if Terra Firma boss Guy Hands, Wormsley’s former friend who is still reeling from his humbling legal defeat by Citi over EMI, decides to put in an appearance...

FROM Chelsea gardens to gardening leave. Some resting bankers play golf between jobs, but Citi’s incoming managing director of UK and Ireland investment banking Basil Geoghegan spent his two-month break after leaving Acision in March climbing the world’s highest mountain in aid of The Ireland Fund.

Geoghegan reached the summit of Everest at 2.30am last Thursday and, ever the banker, he organised a helicopter to whisk him away from the summit to Kathmandu, before flying home to Dublin to spend time with his wife and four daughters before starting at Citi on 4 June.