Aon is preparing to roll-out its service 'fee card' to the London market. This will list the fees it will charge underwriters in the future.

Aon specialty group chairman Jonathan Palmer-Brown, who is spearheading the initiative, said the broker was in negotiations with the London subscription market over the amount it will charge for the services it traditionally performed for underwriters.

It is understood the fees range from 3.7% to 5% depending on the type of work supplied.

He said: "We said before Christmas last year that we wanted more transparency in the marketplace.

"We are now going to publish the fees we charge for all types of services ranging from manufacturing the policy wordings to supplying the loss adjusting services."

He added that the negotiations on pricing is on-going because "before the client may have picked up the cost of the services, but now the underwriter will be charged".

"This is something new to them."Aon had the full backing of the FSA on this issue, he said, because the pricing structure would lead to more efficiencies in the market.

Aon is not the only broker to question the amount spent on services in the London market.

Marsh chief executive Bruce Carnegie-Brown has made it clear that charges are one of the cornerstones of Marsh UK's new business plan to be launched next month.