On the one side, the IPE is offering a fully electronic dealing environment for the first time, having shut down its floor last week where “open outcry” face-to-face trading had taken place for 25 years.

Nymex is providing open outcry trading on a makeshift floor in Dublin while it waits to open a London dealing room, probably in six months.

Observers say the real battle will begin once Nymex opens in London. The IPE has pioneered the flagship North Sea Brent crude oil futures.

Nymex made an initial attempt to break into the Brent market in September 2001, but this was scuppered by the events of September 11. Most energy business insiders do not expect both exchanges to survive within the same time zone.

The IPE says it is unable to comment because it is bound by the rules surrounding the planned float of IntercontinentalExchange, its US parent, later this year. But insiders were indicating a “business as usual” approach to the new competition.