The City Diary: Wheel keeps turning: Work's not just for fools and horses – ask The Plumber

Slackbelly exposes The Good, The Bad and The Ugly of The Square Mile

Two years ago, Paul Davidson, the controversial entrepreneur the City knows as "The Plumber", floated his Fluid Leader Group. Humbly, he proclaimed that he would turn it into "the biggest conglomerate in Britain".

Not yet, he hasn't. In fact, shareholders watched their investments drip away, Davidson left the board and, in January, the shares were de-listed from Plus Markets, the junior stock exchange.

That all followed Davidson's infamous spat with the Financial Services Authority (a verdict of market abuse was spectacularly overturned after he proved that an FSA official met with a member of the appeal tribunal during the trial) but he's now attempting another audacious comeback.

The Plumber has been in America promoting his latest fantastic invention – some gadget that plugs oil leaks, just at a time when it might just come in handy for BP in the Gulf of Mexico.

"I've just spoken with a BP oil trader and an engineer," he claims. "This definitely works." Next year, Rodney...

GLG goes all coy about its Man Group relationship

Hedge fund giant Man Group is taking over its rival GLG Partners in a £1.1bn deal.

Noam Gottesman, the chairman and co-chief executive of GLG reckons the deal is "transformational" while Man Group's chief executive, Peter Clarke, gushes: "The commitment of the principals of GLG and their enthusiasm for the combination is evidenced by their receiving all consideration in Man shares."

Still, I wonder, has GLG had any positions, short or long, in Man Group this year?

"Ooh, erm, erm, ooh, erm. Well there are 40-odd funds," stutters a GLG spokesman. Indeed. So there might be a good chance that one of them has made a Man Group trade.

"Ooh, er, well, let me get back to you," he says, unconvincingly, before disappearing for good.

Man Group happily volunteers that it has never taken a position in GLG shares – although it has invested in its funds.

Why is GLG being so coy?

Morley breaks the Coutt's chief executive's 5kg rule

Michael Morley's first year as the chief executive of Coutts has been quantifiably ground-breaking. Every chief executive of the private bank is said to put on five kilos in their first year in charge, and at the last weigh-in in January Morley was 60 per cent there. So what are the scales saying now he's been in the job 12 months? "I'm pleased to report that a modest fitness regime of walking to work everyday and cutting out desserts means the weight gain is below the five kilo mark," he beams. His own little place in banking history, then.

South Africa dream defeated without a ball being kicked

Therese Coffey, the former finance director at Mars Drinks and the new Conservative MP for Suffolk Coastal, has got off to an unfortunate start.

A staunch Liverpool and England football fan, Coffey has booked herself on a trip to South Africa next month which includes tickets to watch England play Algeria in Cape Town, and Slovenia in Port Elizabeth.

The best laid plans, and all that. The emergency budget has been called for 22 June, which falls in the middle of those two fixtures. That means Coffey will have to stay in London and forfeit the cost of the trip, as the tickets are not transferable. "Obviously I'd rather be representing my constituents," she smoothes (not entirely, convincingly), "but, I've lost quite a lot of money".

How much? "I'd rather not say. Cash is tight. I've just had to extend my overdraft."

Time for a debut expenses claim?

Vodaphone's golden duck on decisions

Is there any decision that Vodafone executives can get right? Speculation that the mobile group's move into India is putting its planned dividend rises at risk refuses to die, while in December the company finally gave up its 12-year sponsorship of the England cricket team. That retreat came just in time to miss out on the side winning its first major tournament last weekend, after 35 years of trying. The network you can depend on, as Vodafone likes to say.

UBS holds fast over National Grid positioning

UBS, the Swiss investment bank, was quick to reiterate its "buy" recommendation on National Grid after the group's shock rights issue announcement last week upset investors and prompted a 7 per cent slump in the share price. It had little choice, I suppose. Just 10 days earlier the bank's crack analysts had suddenly altered their view, upgrading the shares from "neutral" to "buy". Solid work.

Egos firmly intact in the Busson/Thurman household

Ultra-rich hedge fund boss Arki Busson modestly reckons that his dashing looks have been a handicap during his business career. Similarly, his fiancée, the actress Uma Thurman says: "When I was younger, if you weren't the girl next door you couldn't get those really human parts. Even now it's a bit challenging. It was frustrating to me. Not that I particularly minded playing the exotic."

Thankfully, neither has ever been hamstrung by self-effacement.