Michael Lawrence, the last incumbent, claims he was ousted by a cabal of market-makers, including Smiths. But Mr Marks insists that Mr Casey is not "the market-makers' man".
"He's an accountant by profession, he came from NatWest, he wasn't involved in that side of the business," says Mr Marks.
"The debate has moved on. We're going to have an order-driven system for Footsie 100 companies [something Mr Lawrence was keen on]. It wasn't the change, but the process of change that annoyed people."
When not pulling the Exchange into the modern age, Mr Casey will probably be found at his small cottage in Dorset with his wife and three children. He also enjoys sailing and shooting - "not very well," according to one observer.
The papers may be full of the evils of smoking, but it is still compulsory for all executives of US tobacco giant Phillip Morris to ask for a seat in the smoking section whenever they fly anywhere on company business. Even if the executives involved are non-smokers, which a number of them are. The condition is written into their contracts. Pass the ashtray.
The antics of Paul Gascoigne and his team-mates apart, Euro 96 does not seem to be fostering much Euro-togetherness among the competing teams, at least not in Yorkshire.
Indeed the county is considered something of a culinary disaster area by the Continentals staying there.
The Danes, the Spanish, the French and the Portuguese are all steadfastly refusing to eat any British beef.
Only the Bulgarians are tucking into the stuff. Scarborough's town council have paid pounds 25,000 to put the Bulgarians up in a local hotel, and apparently liberation from Communism has given the players an insatiable appetite for meat of all kinds - the more beef the better.
The Portuguese, in contrast, have parked a huge refrigerated truck outside their hotel near Rotherham, in which they keep all the food they'll need during their perilous stay in the UK.
The truck also contains huge amounts of water. Apparently Yorkshire Water's disastrous performance during last year's drought was headline news in Portugal, and the poor chaps are fearful of going thirsty during their stay.
Vic Cocker, the chief executive of Severn Trent who last year told you to concrete over your lawns to conserve water, is ebullient following the company's sparkling results. Observers, noting that Vic's brother is none other than Joe Cocker, the famous singer, are even saying that Severn Trent is finally "up where it belongs".
Joe Cocker was a gasfitter before he became a rock singer in the Sixties - clearly utilities run in the family.
When Tom Cruise appears in the soon-to-be-released blockbuster thriller Mission Impossible, the big-screen version of the television classic, he will be wearing British suits. Timothy Everest, a contemporary tailor based in Spitalfields, London, has achieved this notable export success. "The person styling Tom Cruise wanted a Nineties interpretation of a Sixties TV show," said Timothy. It was difficult to find anything suitable off-the-peg for the pint sized thespian, and Timothy supplied him with a "high quality wool pinstripe to produce a three-button, slim- fitted jacket with flat-fronted, slim trousers". One of the biggest problems was supplying replacement trousers - "they were always getting trashed in the stunts".