UPDATE 2-Aviva says CFO to leave; no successor announced

* Spokeswoman says Scott won't seek new executive role

* Shares close 3.3 percent lower (Adds analyst reaction)

LONDON, June 18 (Reuters) - British insurer Aviva (AV.L: Quote, Profile, Research) on Thursday announced the surprise departure of its finance chief, Philip Scott, sending its shares lower.

Aviva, Britain's second-biggest insurer by market value, said Scott, 55, would quit at the end of the year. He has been Aviva's chief financial officer for less than two years, having previously headed the group's European division.

Aviva shares closed 3.3 percent lower at 318.5 pence, making them the third biggest faller in the FTSE 100 share index, which settled little changed on the day.

"It's a surprise, so in that sense it's potentially a negative," said Fox-Pitt, Kelton analyst Raghu Hariharan.

"No successor has been announced, and it seems a bit sudden."

An Aviva spokeswoman said Scott, 55, does not plan to seek another executive role, but may take on additional non-executive responsibilities. He is currently a non-executive director of drinks maker Diageo (DGE.L: Quote, Profile, Research).

"I would like to thank Philip for his considerable efforts on behalf of the group over many years," Aviva chief executive Andrew Moss said in a statement.